The only difference (as far as I know) between the 2 drus is that suboxone has an added OPIATE BLOCKER. If you take suboxone and then try and take a vicodin, you will not feel the euphoria from the vicodin. He may have some symptoms and an adjustment period while switching (such as headache, sweating)
If no one is going to taper him off and you both feel its time you could always do it yourself. I mean I tapered myself off, you just have to go really slow. I mean really, really, slow. Good luck