Very difficult to respond to these kind of emotional messages. When I get similar letters or emails , I have responded in the following way - I really don't know how it goes down , but at least it is a response of sorts. In the early months after I faded , I used to write longer messages but have long since learned my lesson - they invariably get twisted & end up biting me back - one brother who sent me a very similar email accused me angrily of "rejecting his help & knowing better than the GB" and tried to get me into trouble with my elders when I wrote a short letter , so it really isn't worth it.
Option 1 -very non-committal - " Thanks for your concern - I appreciate it & know that it comes from the best of intentions. "
Option 2 I sometimes add , depending on the individual - " If I may respond , in truth neither of us know for 100% sure whether or not either you or I will see my father again , or even whether he will be resurrected. Thankfully , neither you or I are the judge - that decision is in God's hands and he has appointed Jesus as the judge. "