Grace, I'm praying that you'll be able to overcome your fears of what will become of him and have him leave your home. It is sooo hard, but its better than your whole family being destroyed (my husband and I were separated for a year...difficult child and her manipulating were a big part of our problems). It is also extremely hard on the other children to have their family in constant turmoil over difficult child.
I am still struggling each and every day with fears about what's happening in my difficult child's life, but I do know that I can't control the bad things that happen to her, nor can I do anything about the choices she makes. She will NOT live in our home again for more than a week or so. Been there, done that, and it just doesn't work!
Do go get some help for yourself! Also, I go to Families Anonymous, which has really helped.
