How do I fix my stirring wheel being off center after break caliber worked on

What is your question?

My husband was working on the break caliper on my van thinking that's why the breaks wouldn't work.. well turns out he just knocked a hose loose when he replaced my spark plugs... but once he fix the hose and the breaks work again.. now my stirring wheel is off center I have to keep it turned right about 15 degrees to keep the vehicle driving straight, how can we fix this and what happend?