Chic, you are smart and organized.
Set yourself up a list of tasks and make a specific time to talk to your son in law and daughter whose assistance and back-up muscle you require. Please be honest about sharing with them, because this stress is eating you alive and it WILL affect your physical health, it just beats you down when you have to live with him every day.
no drama, just tell them what you think needs to happen, it's your house, you live it, not them. I would say stop sheltering and not wanting to "bother" anyone else and preserve your own sanity. As you are getting older, (sorry i don't mean for that to sound snotty) it is getting harder. What is going to be in 10 years if you don't act now? You will be more upset and he won't have moved in a forward direction.
make a list of what you expect him to do, hand it to him in writing and give a copy to your daughter he has NO RIGHT TO DISRESPECT YOU IN YOUR OWN HOME, if he wants his little room, he has to come out and listen to the owner.
these are just suggestions about what I would, i'm not trying to tell you what to do, big hugs and a big bowl of ice cream to follow.