This situation has all the potential in the world to go nuclear and I suspect it will.
I'd personally have a difficult time keeping my emotions in check and honestly, don't think I could be responsible for my actions.
For respect for the Aunt, I'd try and speak to her alone, tell her what you know and if she asks you to make peace with this guy before she goes to meet her maker, I'd probably say OK to keep her happy but it's not what I'd do.
Once it's all over, I'd have nothing more to do with family.
I'd personally have a difficult time keeping my emotions in check and honestly, don't think I could be responsible for my actions.
For respect for the Aunt, I'd try and speak to her alone, tell her what you know and if she asks you to make peace with this guy before she goes to meet her maker, I'd probably say OK to keep her happy but it's not what I'd do.
Once it's all over, I'd have nothing more to do with family.