He is probably going to commit fraud with your mother's ID, of which he has no legal purpose or need for. He will likely sell your mother's ID. Since she is dead, there won't be anyone for years who will find out and that will cause all sorts of bad records. Not what you want or any family member would want. DON'T give him the information. Tell him you don't know it. If he says you do, tell him you don't. Stand your ground. If he has reasons, tell him you just didn't keep the records - you turned them into the IRS soon after she died. He's a meth head so, he will believe you. If he doesn't, his tough luck. Under no circumstances, should you give him your deceased mother's SSN or ID or any personal information. He is ONLY entitled to assets that were Willed to him and the Executor/Personal Representative will look after that.
Certified Paralegal, with 25+ years' experience & with Wills & Estates law experience.