There is nothing you can do.
My daughter does r and they said there isn’t an issue until she gets her adult teeth.
Most kids grow out of it.
And they don’t know they are doing it .
My husband Grindr his teeth in his sleep sometimes and he didn’t know until I told him.

I work at a dentist office. They recommend going in by their first birthday. I know teeth grinding is common in small children. There’s not much you can do for a child. As a teen or young adult you can get a splint or mouthguard. For a child all you can really do is wake them from their sleep and tell them to stop. Unfortunately there aren’t many fixes for children until they get their adult teeth.

When do I start bringing him?

My dad and hubby do as well. My dad had to get a special mouthguard from the dentist to help with it