Hugs in return for your messy and hard situation, Mick. You are so right about caring for ourselves--it reminds me a bit of the flight instructions, In case of an emergency, put your mask on before helping others. If we don't, our compassion will run out of oxygen, too.
I expect some critical responses to this piece. There are many people living in much more difficult circumstances, for much longer periods of time. Living with older or adult children is, I think, often one of those more difficult circumstances. You really do have my wishes for a peaceful and compassionate way through the hard mess of it all.