I'm not in your situation but... I resigned as an elder and stopped attending meetings at 30 revealing that I had never believed in god. Family upset but not shunning. When I came out 1 year later one of my brothers and his family decided to shun me despite me not being disfellowshipped. We discussed their hypocrisy of finding my disbelief in god easier to deal with than me having a boyfriend but hey ho somehow the gay thing was much worse.
Sorry I can't help, but even more sorry your kids have behaved like this. Hopefully time will make a difference.