Why does my aunt keep showing her body to my boyfriend?

So, my aunt has been making my boyfriend super uncomfortable by repeatedly showing her body to him. First, it was about body types, and when he said he liked my body, she started acting weird, asking him if he thought she was beautiful and even tried to get him to touch her. Then, she showed us her gym progress (lifting up her dress) and later insisted on showing her breast biopsy scars. Both me and my sister have asked her to stop, but she doesn’t take us seriously and calls us uptight. We've tried talking to our mom, but she thinks we're exaggerating. What can we do to get her to respect our boundaries? #familydrama #boundaryissues