L.J.
You sound like you are doing a good job. It is awfully hard for us to let our kids fail, but it is probably the best thing we can do for them. You and your husband need to explain to the 18 year old that he is legally an adult and that his 15 year old girlfriend is not. The age of consent in California is 18 and in Florida I think it is 16. You can't control him but you can at least give him the facts of life.