We're really glad that you took the time to reach out for some help. While it seems like dad may feel as though he is in over his head or thinking about giving up, you certainly seem to be taking the initiative on this.
First off, it is important to remember that you shouldn't be the one to take the lead on this...that is dad's responsibility. If he feels like he doesn't know how to parent there are parenting classes, parenting videos, and other parenting resources available. Try to help him get connected with these in your area. If you aren't sure how to find any of these, you could always give our Hotline (1-800-448-3000) a phone call. We have a database with referral information for agencies all across the country. We could help point you in the right direction to find these resources.
In the classroom, there are a couple of things you can do. First, set some clear guidelines and expectations of behavior for the whole class...not just this one particular student. You could go so far as to create a "No-No" chart with a list of inappropriate behaviors. Make it clear what behaviors will not be tolerated. Respect for others is demonstrated by specific behaviors (listening, not touching other people or their possessions, talking politely, etc.). The opposite of these behaviors (touching others or their things, talking while others are talking, verbally putting others down, etc.) are all inappropriate behaviors you could put on the "No-No" chart. Also on this chart could be a list of consequences the students will receive if they do any of these things. Putting it all out there for them to understand will help clear up any confusion.
Also, it doesn't have to be called a "No-No" chart. If that name seems silly then go ahead and name it whatever you would like; the contents of the chart are more important than it's name.
You could also take some time every day (just a couple of minutes) to model good behavior and to give the kids a chance to practice it. Taking time to practice good listening, respect for others things, and how to talk politely are all topics you could think about covering during these practice times.
The only advise I have (from experience) take away the valuables he has! He earns them back one at a time by showing respect. He must understand that you can grant him forgiveness once (take everything away) each show of respect he can earn one thing back (you decide, keeping the most valuable), if lack of respect happens....whatever he earned is taken and HE has to give it away. YOU HAVE TO MEAN WHAT YOU SAY AND ONLY SAY WHAT YOU MEAN. I am learning this from experience and it does work!!! Watch Supernanny or listen to Dr. Phil
My first step would be to talk with the parents. If this isn't possible then you have quite a problem on your hands. What kind of behaviors are you seeing? You could try a behavior chart with very specific goals (Sam will say please when asking to use classroom supplies). When a goal is met give the student a reward and add a new goal. If he is physical with other students I would keep his desk away from the other students and in front by the teacher at all times. Good luck!