You have been more than kind, loving and generous and from your post it looks very like your son is taking blatant advantage of you.
Who legally owns your house?
Who is legally responsible for the upkeep of this house and all the bills?
Ok, I see it is you.
You need to speak to your other son and explain what’s happening, then both of you need to sit down, calmly and quietly, with your son who’s living with you and his wife.
Do this when the children are in bed and very calmly tell them that if these living arrangements are to continue, changes need to happen.
1. You must agree a scale of both payments and help around the house.
2. You need to put in place a date by which your son and his family will move into their own premises.
If you don’t do this your son will take over your entire home and destroy your life.
There are many things you can do to help manage your loneliness and grief which your son has so alarmingly exploited.
Seek assistance from a solicitor and if your son has threatened you in any way, ever, physically, financially, emotionally or mentally you really need to consider speaking to the police.
What he is doing to you in wrong in every sense.
Please consider grief counselling and seeing your GP.
You are not alone and you deserve support.