You are doing some planning ahead and that is a great thing.  If your son is a minor nothing is needed.  If he has reached majority then you need to do some paperwork for guardianship (limited or otherwise), conservatorship/ medical POA, etc.  Here is a link to look at and then seek consultation. Good luck.https://www.autismspeaks.org/family-services/tool-kits/transition-tool-kit/legal-matters