My friends mom is dead, but I want to do some genealogy for him, and don't know his mom's maiden name.

Why not ask him, would be the simplest approach to take.

Doesn't your friend know his maternal grandparents' last name? Alternatively, if he knows when and where his parents were married he can order a copy of their marriage license from the county clerk - it will list his mother's maiden name.

I would hessitate to answer this question with any other answer than "ask your friend" because this information is often used for a security question to get access to people's passwords, access to banking information, etc. I would not be looking up this information about a friend's family without the friend's knowledge and "surprise" genealogy research seems an unlikely story to me.

I would hessitate to answer this question with any other answer than "ask your friend" because this information is often used for a security question to get access to people's passwords, access to banking information, etc. I would not be looking up this information about a friend's family without the friend's knowledge and "surprise" geneology research seems an unlikely story to me.

That's a good point.