Medication helps me
a) to remember stuff for the minute or so that it takes sometimes to get around to it and
b) to deal with interruptions better in that I can return to the previous task more easily.
I'm still very susceptible to sensory overload. But I find that clearly communicating how I'm doing with the people around me and excusing myself when I'm overloaded (or tired or whatever) works quite well for me.
Case in point, I was just playing a multiplayer online game with people and realized that I'm just too tired to properly process what's going on anymore. So I told everyone I'm too tired to keep going, wished them a good night and told them I'd be happy to play with them again tomorrow. Younger me would have pushed on, resulting in drama and loss of self-control.
All that said, you might be suffering from something else entirely, so getting diagnosed is still the best course of action, IMHO.
He'd probably adore this admirable abundance of alliterations.