i agree, now is the time to put your focus on what YOU need. the boys are almost 18....and can and should begin to make their own decisions, REGARDLESS of how it might look to a parent. it's tough, but it is also important to empower our children to take control of their lives.
i'm sorry i don't recall the backstory with the dds but you have the right to NOT have contact with ANYONE who is cruel or disrespectful.
your health is numero uno now. take every measure you can to assure the best of outcomes. i wish you every good thing.