Elderly blind Mom says boyfriend stuck tongue in her ear. What do I do?

Hi..Could use some help. My mom is 83, blind and is not in too good shape. I am her only child and her caregiver for many years. We have a very close relationship. Last week she told me my boyfriend when giving her a hug goodbye shoved his tongue in her ear when I was in the other room getting ready for us to go to the movies. A sitter was right by their side and said he hugged her and gave a kiss on the side of her face but no tongue in the ear. Naturally I told my mom that I while I think she perceived this, I do not think it happened and reminded her that she said last year that her gay hairdresser did it and many years prior a lady neighbor. This is really a weird situation. It has been a huge strain on my relationship with my mom and boyfriend. She says blind people are victimized and she was very angry at my not believing her for days and days..lots of crying and fighting. My boyfriend has been very supportive but naturally I have kept him away. My mom says she would be afraid to be around him again and would have to hide in her room. My mom is quite sharp mentally. But does take ativan a few times a week and hydocodone cough syrup a few times a week as well. Any thoughts greatly appreciated. I am worn out physically and emotionally.