As noted by Nickolas and others, GM seizures have no correlation to stress. I have had GM seizures and went to the extent of visiting a Harley St neurosurgen for answers. None. They are not (usually) life threatening, just look bad. Interestingly, I have not had one since separating from jws 13 yrs ago.
I too have gone through jw divorce/child custody and can only recommend getting legal advice. But at this moment, imo go to a counsellor, get yourself a decent place to live, then start being the best dad you can be.