Let him keep them. One of my special interests as a kid was keys and locks. I had two large Yuban coffee cans full of them. I would spend alot of time examining and sorting them. It was very calming to me, and likely kept me out of trouble. It is not as all consuming as it used to be, but is still there. To this day I will buy a lock that I have not seen before just to see how it works.

Omg I LOVE keychains! I have quite a few. I currently have a Squishmallows Cam the Cat water-filled one on my bag 😊 I'm obsessed with Squishmallows!

I loved key chains as a middle schooler I had tons of them hanging on my purse when I went to daily Mass. I would show the kids and they were captivated by the colors.

Yes you should. He has a huge interest in keychains. My sister who has ADHD loves keychains as well.

Totally could be. My son has a number of special interests. Some unconventional to others perspectives. But to him it’s wonderful. It could be bringing him some sensory input he enjoys. It’s good you have recognised the interest as you can use it as a distraction if he ever suffers anxiety.