I’ve found that when taking drugs to help a stutter it only works as long as you are taking the drug. I know he doesn’t stutter and isn’t on shrooms all the time. So maybe an isolated event. But I know people who have just more or less decided to stop (must be nice) and did. But each case is different and everyone will have different outcomes. I took shrooms a handful of times and mostly it just made me really introspective and scared the crap out of me. No help with my stutter