Eek! I don't know which is worse, him being all googly-eyed over the neighbor lady, or tolerating their abusive son.

Maybe rather than confronting issues he has within your family (whatever those might be, I have no idea), he is shutting you out and making up a nice little fantasy for himself. Neighbor lady = romantic feelings without any commitment. Just a possibility.

It sounds to me like you have pretty good reasons to feel angry and scared. An objective counselor could help--maybe individual, maybe couples.