What? The 3 brothers are the co-trustees and benes? What about Mom? Putting the home in a trust with you and your brothers as beneficiaries would be a gift to the beneficiaries and a gift tax return should be filed. If you got a 1099 for the sale of the home with the trust's name and tax id number then a 1041 needs to be filed. You have a complex tax situation.....see a tax pro or the lawyer who drafted the trust.
