Punish his poor behavior. If he moves in with his father, so be it. It won't last long b/c promising the world sounds great, but it won't pan-out in reality. You need to have a sit-down conversation with BOTH of your sons together. Literally spell-out the expectations using clear language and post it somewhere visible in the house. Next to each expectation, outline a logical consequence.
For example, if your expectation is that your sons will use respectful language towards all members of the family, then a logical consequence for not doing so it to remove communication options for a period of time (no internet, no cell phone, no home phone, whatever you have). Be realistic about the time period b/c you have to be able to stick to it- a day or so is enough.
On the other hand, if you notice your boys abiding by the rules, acknowledge it! I wouldn't suggest purchasing items b/c you will eventually run out of reasonable options, but you could certainly "buy" some family time- order their favorite take-out, rent a movie of their choice or something else that reminds them that respecting their family will result in happy times with their family!