Sorry to hear about this, GP. He's probably still suffering grief from the loss of your mom, and probably ought to see a good local counsellor / grief counsellor, so as to finish the necessary grief work more effectively. On top of that, he is still adjusting to the relocation, and the loss of the place where he was used to living. You don't mention his age, but the older one gets, the harder it is to adjust to such changes in one's life. A counsellor could really help. Also, make sure he continues to feel involved, not only in the life of you and your family, but also in that of your brother. Plan regular family outings and activities, and maybe find some area of your life where he could help, whether as a handiman, baby-sitter or whatever, so he can still feel useful rather than redundant.