I'm so sorry, I really don't know of a home remedy for teeth grinding. If one of my children or grandchildren were grinding there teeth while sleeping I'd try giving them something to relax them at night, like chamomile tea. I honestly don't know if it would help but I'd think it's worth a try.
A friend of mine had that problem and went to the dentist about it and he gave her something to wear in her mouth at night to protect her teeth. She said it wasn't too uncomfortable to use, it was worth it to her to keep her teeth from grinding down and cracking.
Maybe one of our regular visitors will know some tips on teeth grinding and home remedies.