You have to admire the little guy's persistence :) I'd try contacting an O.T. to see if they have any ideas. We're in the middle of switching providers right now, but I can ask for advice once we get established.
I would get a referral for an Occupational therapy evaluation. Your grandson may have sensory needs that can be addressed during OT sessions. You can pursue this through his primary care physician and/or school based IEP/IFSP team.
My son did this also when he was younger. His OT had given us some chew tubes and that really helped. We never went anywhere without his chewies though. For him, it wasn't an issue with the buttons, it was him needing to chew on something.
That is a good idea, but unfortunately(?)he knows how to get velcro apart, open snaps and unzip. He likes to take his clothes off all the time so he can't wear a pullover shirt. We put a belt on his pants and tuck his shirt inside. I am sure he will figure this out soon.
Thank you for the suggestion, Debbi
Thank you for the suggestions. We are new to this. He hasn't gotten his therapists yet. Still waiting. Problem with insurance.