I'm not sure the point you are trying to make.
A lot of things that you slough off as "if's" must go right for the OP to benefit in this situation. At the moment he's got 50% ownership in a house occupied by a guy whose threatened him and no legal means to have him removed from the house. I'd love to see another option for him but absent that, it seems his only out is to give the guy his 50% and be done with it, because the guy whose benefiting from the life estate has no reason or motivation to buy him out.
If the OP dies first his heirs get nothing, yet, the OP must endure the angst of whatever may happen while he's still alive. Sounds promising, huh?