My son is 41yrs old and disabaled and is getting disability benefits since he was 15. His father and I are no longer married. His father ia 62yrs old. Can my son benefit from his father's SS benefits when his father retires?
Probably. Assuming that your son isn't married, it sounds like he would likely qualify for disabled adult child's (DAC) benefits if and when either you or his father file for Social Security retirement benefits (https://www.ssa.gov/OP_Home/handbook/handbook.03/handbook-0323.html).
You don't mention what type of disability benefits that your son currently receives, though. If he is receiving Social Security disability benefits (SSDI) based on his own work record, then he could only receive the higher of his SSDI or DAC rates. And if he is receiving SSI (Supplemental Security Income), those benefits would be offset roughly dollar for dollar by the amount of any DAC benefits that he receives.