Surely asking the young lady to put her magazines in her room when you visit shouldn’t be construed as too outrageous, even if she does mumble something about her “frummie relatives” under her breath. She’s not a young man, so she likely doesn’t understand your concern.
We once went to visit a Rosh Yeshiva for Shabbos. His wife told me that when she gets catalogs from department stores, she still pulls out the pages with lingerie and bathsuit ads. She said “even though the RY is an old man, he’s still a man”. His daughters used to cut out inappropriate pictures from news magazines for him. We stopped buying the NY Post because there was almost always a scantily clad woman on page 2, and my teenage sons didn’t appreciate it.