Mom's house is in an irrevocable trust in my sister and myselfs name and maybe hers also. What would be Medicaid's position?

Here in NY if mom has a life estate, the rental income has to go to her care. If the house is sold while she is still alive, she is entitled to a portion of that as well.

First thing you've got to find out is whether or not the trust is revocable or irrevocable. And, of course, whose names the house is actually in within the trust. You simply don't have enough information to get a reliable answer.

I'm going to take a WAG that it's in a land trust, revocable. Mom as the principle beneficiary; you and your sister as contingents. (That's the most common kind of trust for a home.) If that's the case, unfortunately, the house is fair game. It's my understanding that Medicaid will allow the home to continue being rented if it generates 6% net income. (I'm not sure about that.)

Your understanding that Medicaid can't go after the house for recovery is incorrect.