Heck, everyone knows that Spirit still loves his ex-wife and daughter. Small wonder he doesn't proclaim it from atop Shibusen as Black Star would do.
He's a young dad who really sees himself as not really worthy of being Maka's father because of the way he acted before but that won't stop him from doing anything and everything he can do to help - even if it makes him look like a total jerk/doofus in the end. He's being a doofus for his daughter and that's what it's all about at the end of the day for him. I really pity the day if someone hurts Maka badly in front of him in a combat situation - maybe then we'll see just why he's the strongest of the DeathScythes.