Daycare Giver needs advice on parent, what would you do?

I run a home daycare and have a bit of a strange family. Mom is a little odd in a goofy way, but Dad just plain creeps me out. It isn't that he has said anything wrong. He barely speaks, kind of stares strangely, sneaks up quietly watching me, and freaking out my teen girls too with his learing quiet behaviour. My husband has tried some friendly chat, and can't get through to the guy. Do you think he is a total snob or just super shy? Any advice? I am fairly outgoing and I am quite attached to child and don't think it is fair to give notice and let child go, just because dad is oddball. I don't think it would be appropriate to say anything to the wife to let on I think her husband is weird. Help! What would you do? Continue to grin and bear it?