My son is away from home, and doesn't want to wear diapers or get anyone to help him change them. What should we do?

Tantrums! If he is under 2 years of age and dictating to you it is a like temper tantrums. I would just hold him down, put the diapers on and then put his regular clothes on and ignore his tantrums.
Age? . Why is he away from home? What's his age? Why is there an issue with diapers? The parents are in charge, even of unruly toddlers. What you say, goes. Your story is rather odd. Do you mean at day care? Most two year olds begin to resent using diapers, but haven't developed the ability to use the bathroom yet. They're confused and frustrated. Depends a lot on the circumstances.