Teeth Grinding

My husband grinds his teeth all night long! It’s so annoying. He’s been to the doctor and they said to try magnesium (relaxes the muscles) but it doesn’t work. I’ve researched guards he can wear but they don’t sound comfortable. Anybody else with this problem? Any suggestions on what to do or what might be causing it? It’s been going on a long time and it’s every night. 😩