Coming from the world of education and I'm not sayin this to be a dick but you have very little legal grounds in terms of bringing suit against the school district. Remember, everyone is entitled to a free public education and there are laws (individuals with disabilities education act) that makes it real tough.
Second, unless it is a private school a teacher or group of teachers should not be fearing for their jobs...that's why there is a union, CBA and tenure. It takes a whole hell of a lot for a principal and school district to fire a tenured teacher...I'm talking minimum 6-8 months.
Third, when you go talk to the principal make sure you make him aware that if the situation is not resolved you will be going to the Superintendent. Once the Superintendent gets involved all bets are off for the principal. Not only do Principals hate it when their boss gets involved it makes them look like ****ty and they don't have control over what's going on in their school.
Biggest thing, don't go in there making threats. Go in calm, cool and collected. Make sure you address all your concerns and be upfront about going to the higher ups if the situation isn't being handled. Remind him that your child is also entitled to a safe school environment and if one isn't provided by the principal you'll go higher up.
Hope this helps, if you need any other advice PM me and I'll be happy to advise you as best I can.
I get what you are saying. The school my son goes to unfortunately is not affiliated with any union. Here in Nebraska it is a right to work state, unfortunately and the teachers in grades k-5 do tend to have very short tenure here. My big issue was how to address it considering he has blown me off several times about this over the last 3 years. If this was normal bullying like what I understand bullying to be I would just expect my son to tough up and deal with it but my son is really being harmed here. I really couldn't believe I got blown off when he stabbed my son through the hand with a pencil (three stitches and a round of antibiotics later and the kid got nothing.) I know I am really angry now and I'll be more chill when I talk to him tomorrow. Can you explain at all where the line for protecting a disabled child and protecting the safety of mine ends? Can I request his parents info like a phone number?