I don't have grandchildren, so I have no hands on experience.
If it were me, I'd be calling, reporting these conditions to the Dept of Family and Children Services. But like I said, I haven't been there so I don't know what it takes to get them involved.
I do know I can pray for you, your son and these precious grandchildren. There is power in prayer and I'm adding this to my prayer list.
Hugs,
Hangin' In