Father dies no will who's entitled to property eldest son or girlfriend/wife?

My friends (Johnny) just found out his dad (Jesse)committed suicide in March 2009. Johnny is the eldest son. Jesse is listed as owner of his property as being a single man for the last 20 some years. In 2002 the deed changes and has a lady (Amy) that he cohabitated with as being a trustee to the property. They lived together for several years and we don't remember them being married but, on the deed it has Amy's last name the same as the Jesse's. Regardless if they were married isn't the son entiled to (as heir) some of the property? He found out his dad passed away a week ago. He hasn't had contact with his dad for years. But Amy said he was trying to get a hold of his son before he committed suicide and would cry because he couldn't get a hold of him. She was able to contact Johnny to tell him his dad died and had left something for him. When we arrived she never mentioned or gave him anything...Based on the situation is he entitled to the estate or is Amy entitled to the property. I realize four months have passed. What's the situation if they were married? What would be the situation if they weren't married and they just lived together for 15 years? There is no will.

+++++This takes place in the state of Arizona+++++

He had no contact with his father and he feels entitled to something? The father tried desperately to contact him before he died and was unable to reach him?

If the deed is in the girlfriend's name as a joint tenant, she is now the sole owner of the house. No probate court can interfere with that. The house is hers. He has no legal recourse.

It's sad he wants something from his father when he chose not to have anything to do with him all those years.