I'm going to offer my 2 cents which is going to come across kind of strong and for that I apologize in advance as I know you are just wanting things to improve for your son: if it was my kid I would quit my job and stay home with them, move, totally alter expectations for their and my future -- whatever it took to decrease their stress level, before putting them on risperdal to control behavior that is not life threatening.
Risperdal is an antipsychotic, it is a fantastic medication for people with schizophrenia who can't control themselves, and people with behaviors that are life threatening to themselves or others. On balance in those cases it can be better to substantially alter the person than to have them remain a danger. Yes it is used a lot in people who aren't a danger but there are risks. In rare cases it can have permanent side effects that simply don't go away when the medication wears off, look up tardive dyskinesia on youtube and see if you are willing to risk that to avoid this year's tantrums.
It sounds as if this is a hard situation for everyone and I hope you find a safe way through it.
Polly
