Pre, this may or may not be what you'd like to hear, but this is coming from my heart .... the first person for you to take care of is yourself. You. There is so much going on in your life, with serious health issues and emotional issues, that the best way you can support your DD and grandkidlet is to take care of yourself first. If the stress gets us too far down, we can get to the point where we can't even listen with compassion.

Please take care of yourself first. That's the least selfish thing you can do!

Maybe sometime soon your daughter can be convinced to see a family therapist, ie, one who will see mother and son together so she can be there to make sure her son is safe. Where I live there are a number of therapists who see parents and kids together in order to work on the family dynamic and to see how they operate together. Maybe there's something like that your daughter -- her, not you -- can look into. If she doesn't want to, then acceptance is always good, too.

Take care!