My son, aged 11, has small weak hypermobile fingers, it’s like watching a spider try and grip something 
My concern is public locks - he’s been stuck in a restaurant bathroom before (had to call reception), I’ve had to leave him unlocked in a caravan because I was afraid he wouldn’t be able to open the door in an emergency. Mostly we advise him not to lock doors but we’re getting to the stage that it’s age appropriate to do so.
we’ve obviously been working on hand strength etc but I think he is just like this.
are there any aids etc he can have or does he take a can of wd40 everywhere to loosen locks?
advice would be appreciated