[squiffy]

Well, the part about your brother having to use the money to pay down his mortgage is the key to your OP.

If your mother's wish in that regard was expressed orally, then the bottom line is that it would probably be ILLEGAL for you as executor to even attempt to enforce that oral wish.

As an executor, your legal obligation is to comply with the written wishes of your mom as expressed in her will.

If it's in writing, signed by your mom, with witnesses, that's legally enforceable.

If she told you something orally, you probably cannot LEGALLY try to comply with it.

I think your instincts were correct. But if you are going to be the executor of the will, you also need to be aware of your legal function and legal obligations.

Actually, it might be a very BAD idea to have your mom talk to your brother. If it's not in writing, her oral wishes are not enforceable. And the 1/3 share just goes to your brother with no strings attached.

It's probably best that way any way.