How should I handle this situation?

We moved to a new state about a year ago so I don’t know anyone in the area well and definitely don’t know anyone’s history. My 10 year old started playing softball and one of her coaches is the stepdad of one of her friends from school. The friend doesn’t play but her mom is at every practice and game to cheer the girls on. I recently found out from the mom’s sister that the friend lives with her paternal grandparents and her maternal grandmother has every other weekend visitation. The friend couldn’t come to practice the weekend of my daughter’s birthday sleepover because the grandmother couldn’t watch her at practice with the mom. I have no clue as to why mom or dad do not have custody. The mom has started giving me unsettling vibes. She only cheers for my daughter by name, runs to the dugout fence as soon as my daughter gets in from running bases, and distracts her from the actual game. She never met my daughter before softball and has only seen her outside of softball one time for a birthday party for her daughter. My husband tells me to let it go, but I have a very uneasy feeling. I don’t want a scene caused by flat out asking her, and I’m pretty sure she knows I have my eyes on her. I really want to know why she doesn’t even have visitation with HER own daughter but trying to get so close to mine. I just want to know what others would do in my situation.