I'm sorry to read about this - but; since you are getting an attorney for your Mom's estate; leave him $1 and have it clearly outlined in the will THAT IS his inheritance. No detail is required in the will of his behavior, that way he is not omitted and doesn't have a leg to stand on if he chooses to dispute the will. The attorney can guide your Mom during the preparation of the will, durable power of attorney, and advanced directive.
It may read something like this, "I herein specifically bequeath the sum of $1 to (brother's name) and the remainder of my estate to (your name)"...there will be a lot of legal jargon afterwards. It should also include, "I hereby nominate (your name) as the EXECUTOR of my Last Will and Testament" with a lot of legal jargon afterwards.
