XD *Hugs Tara* : }
Also, since I absolutely can't count on Jeffrey to be clear about anything, a bit more fun backstory: Jeffrey's sister Justine killed herself when she was twelve. She was suffering terrible abuse at the hands of her own father, and knew how a gun worked consequently. Jeffrey's powers emerged in about the same moment (Powers tend to appear in high pressure situations in the Dome) but not fast enough.
This incident appears to have thoroughly screwed up Jeffrey, coupled with the slow ebbing away of his conscience and impulse control caused by his powers. Roselyn Valmont ("Rosie"), his daughter, strongly resembles his sister and he definitely associates the two. She's not actually his daughter by blood. He adopted her (Well really, borderline kidnapped her XD) from an abusive home that was about as messed up as his own.
He's been called a terrible father by just about everyone (And he really is :p), but he loves her and I suspect he's doing about the best he can under the circumstances. Not that that changes the fact that he's a terrific monster of a human being in literally every other respect.