Episode 3 (Spoilers Duh!)
So, his meddling into his own past is what caused him to be stuck with Amal Farouk in the first place? Did I understand it correctly? It's a causality loop that was finally closed with last episode.
He was trying to reach his Mom using his powers in the past and that seems to have fried her brain or smth. His papa was too distracted and griefstricken to pay attention to lil' baby David at that moment and since the love of his life was basically a vegetable he gave him away to a foster house or w/e.
This can only mean one thing:
Old Proffessor X is coming to Legion!!! He'll get to meet his Dad in the present, YAY!!!