My boyfriend [34M] struggles with bad breath and I [29F] don’t know how to approach it

My boyfriend struggles to maintain his oral hygiene because he’s been through a lot of health complications and a vice so his mouth took huge a toll. We been together for a year now. He does a lot to compensate for the evident decay but it’s like putting a bucket of water on a wild fire at this point. It wasn’t really noticeable to me but when we started to sleep together, it hit me like a truck, especially when we have sleepovers. I love him so much hence why I can overlook this issue but this is not easy but he recently asked me to moved in with him and now I’m in this predicament because he’s hypersensitive so I fear me suggesting something or even talking about it might crush him. So what can I do in this situation?