My wife and I are about the same age 60. We have a son who is now age 31, was disabled before age 22 and is on SSI. My wife will have somewhat less than a max SS retirement benefit, and I will have a max SS retirement benefit. If she commences her SS retirement benefit before I do, will my son's SSDI benefit increase when I eventually commence my greater SS retirement benefit later?
Yes. Your son would need to meet the same requirements to draw disabled adult child's (DAC) benefits on either your or your wife's records, so if he initially qualifies for DAC benefits on your wife's account he could later switch to a higher benefit rate on your record.
It sounds like there are a number of factors that could affect your family's optimal strategy for claiming your Social Security benefits, so you should strongly consider using our software to explore and compare all of your various options.