My mother gave my brother a life estate in her home. Now she wants to revoke it. Can she?

Depends- call an atty. My family will inherit a share of a farm that was left to two brothers, but with a life estaye to one. He collects 100% of rent because of life estate. The kids on his dead brothers side can do nothing until uncle dies. Bad situation for everyone.

This is complex, as hadnuff above had suggested, contact a lawyer. Look for an Elder Law Attorney in your area.

Call a lawyer.