Coworker with bad hygiene

Hi! I need help, I have coworker with bad personal hygiene. It’s not consistent. Sometimes it smells like BO, sometimes you can tell that they just have not washed their laundry or a musty smell, then sometimes they smell like they drank heavily the night before. I like this coworker and would like to make it as friendly as possible , not formal. I realize sometimes people don’t notice their smell, just like people are use to their house smell. I am also worried that it could be depression of some sort. The smell has only gotten bad over the past few months and they have been working here for 2 years. I just have had other people bring it up to me, and I also cannot take it anymore. I try to limit conversation. I feel bad even saying that. Please give me like the nicest way to nonchalantly bring it up to a friend. I would rather bring it up and have them know about it than other people talk about it. I even offered my glade plug in by saying “hey your office is stuffy do you want my glade plug in?” They declined. Then I had another coworker make the same stuffy comment and offered her air purifier. Also another decline. I feel like I’m beating around the bush.