@nugget:
This year will be my parents 50th wedding anniversary. My mum is a JW my father is not. My husband and I [have] been Df'd and I have 3 sisters. Sister number 1 is married to an elder and is a staunch JW.... Sister no 2 was never baptised and lives in the US. Sister 3 is baptised but inactive and does not attend meetings and lives with my mum and dad.... What I need is some help as to how to navigate this social minefield so that it is a happy time for my parents and not blighted by ill feeling, family arguments over shunning and bad feeling.
In your message, you mentioned something about a "necessary family [business] card," but there exists no such card. What is needed here is reasonableness by all of you. This occasion that involves your mother and your father is to celebrate he and his wife's 50th anniversary, which is family business, and is not an occasion for animosities or bickering over things that pertain to church business.
This 50th wedding anniversary of your parents is a family occasion, so we're not here discussing spiritual fellowship. Even if both your mother and father were Jehovah's Witnesses (and I understand that only your mother is one of Jehovah's Witnesses), this is not about spiritual fellowship, which [is the tie that] the disfellowshipping action [cuts] and nothing more than this.
You say that your eldest sibling -- Sister No. 1 -- is one of Jehovah's Witnesses, and that her husband is an elder, but other than being your sister and brother-in-law, should they attend a dinner celebrating your parents 50th wedding anniversary, they would both of them be as much guests as would you and your other sisters (Sister No. 2 and Sister No. 3).
I suppose your parents could send to Sister No. 1 and her husband an invitation and ask them to "RSVP," but if they should attend your [parents'] 50th wedding anniversary, [no guest] would have no responsibility for who is and who isn't on your parents' guest list. Based on the biases that they hold, Sister No. 1 and her husband might have strong opinions, but despite what they might believe to be true, Jehovah's Witnesses do not shun family members, except with respect to theocratic functions. What this essentially means is that no discussions of a theocratic nature are to take place with you, their disfellowshipped relative, on this occasion.
Should a discussion, maybe one raised by your father, ensue about the Bible, Sister No. 1 and her husband could politely, not rudely, withdraw from participating in such a discussion, but it would [be]a bit unreasonable on their part [-- at least in my opinion -- for them] to move to another portion of the house as your mother does her level best to assist her own husband understand what she understands the Bible to teach as to the matters being discussed when I'm sure Sister No. 1's husband, an elder, could provide valuable input to such a discussion for his father-in-law's benefit. Jehovah's Witnesses are not fanatics. If I were Sister No. 1's husband, I would not be putting my mother-in-law, your mother, in such a position when I might offer one or more [spiritual] perspectives to my father-in-law that could be helpful to him [in] understanding what the Bible teaches.
I don't care how strong the biases your eldest sister and her husband might have against disfellowshipped relatives, [because] for anyone to go beyond what things we teach is for them to impose a rule on Jehovah's Witnesses based on what someone else's conscience might dictate, when every decision that we make must be driven by our own [conscience] alone, not on someone else's conscience. And while I do not know what your father's views on the Bible or on scriptural matters are, I would doubt that he would appreciate what would seem to him to be bickering between two of his daughters over some religious issue to which he doesn't subscribe and in which he has no interest. But this I do know: Such bickering reflects unfavorably upon the Christ, for it is [God's] will that all men be saved and come to an accurate knowledge of the truth. What your father should see is proof that the love that is said to [exist] among Jehovah's Witnesses is genuine.
Love does not become provoked, nor does it look out for its own interests. This is a family function and your sister should not be using it as an excuse to exhibit what strong feelings she might have as to the decision made by [you, her own sister-by-blood and by your husband, her brother-in-law and your husband], to sever their spiritual ties -- your spiritual ties -- with Jehovah's organization as was your right [and your husband's right] to do. Your eldest sister doesn't have to agree with her father's decision to not become one of Jehovah's Witnesses either, as it was your mother's decision to become one of Jehovah's Witnesses [even though her husband decided not to do so], and she has no more right to rail against her own father's decision (so far!) to not become one of Jehovah's Witnesses than she does to rail against you [for the] decision [you made] to sever your spiritual ties with her: Your father is still her father and you are still her sister.
At all times the decision to not become one of Jehovah's Witnesses has been your father's to make and who knows? Seeing how his eldest daughter treats you could cause your father to take a negative view of the kind of religion practiced by Jehovah's Witnesses and alienate him from ever listening to what things his wife might say to him regarding her "church," her form of worship. [The Bible indicates that the wisdom from above is reasonable.]
Christians should not be belligerent, but reasonable, exhibiting all mildness toward all men, even our own disfellowshipped relatives. Maybe you could have your father remind his eldest daughter that he was informed that the wisdom from above is chaste, then peaceable, and then reasonable. To hear this coming from her own father, someone that has never been one of Jehovah's Witnesses, should be a wake-up call, but I'm not really recommending such an approach, just sharing with you what principles are involved here.
Accordingly, if your sister and brother-in-law cannot with a clear conscience attend [this] 50th wedding anniversary [celebration], [that would be regrettable, but] they should RSVP to this effect and this should be the end of the matter. It would just be horrible for your father to conclude based on your sister's behavior toward you on what should be a happy family occasion as to her attendance at his and your mother's 50th wedding anniversary that Jehovah's Witnesses are driven by religious fanaticism. Furthermore, @nugget, as I understand it, this occasion will be hosted by your father at his house, which means that none of his children [will] have any say as to how he chooses to conduct the affairs of his own household [and maybe this fact being communicated to your Sister No. 1 and her husband will resonate with them and they will consider attending].
@djeggnog