Well, it is probably a midlife crisis. But it is his...not yours. This is your senior year...go stay with your Mom. When he grows up again...maybe then you can explain life to him. Do not let him take your joy..if he thinks he deserves to be happy...so do you. Live your life and prepare for your future. He shouldn't even be discussing his financial issues with you or expecting you to bond with the "other" woman. At least not yet...give you time. Go enjoy your high school year..
This from a 50 year old woman who did take on too many of her on parents problems.