Background: My brother's dad died last year, so he lives with my grandma now. My husband, 22, and I, 21, also live with them, so we can help my grandma with my brother, 16, and bills. My older sister, 23, lives on her own with her boyfriend.

Backstory: About a month ago, my sister wanted to attend an all ages rave with her best friend. We'll call her M, and she's 24 years old. My brother wanted to go. I advised against it, but since I don't actually have custody over him, I didn't have a say. Our grandma let him go to this rave.

Present Issue: Ever since the rave, M has been messaging my brother selfies on Snapchat. There's nothing sexual that we know of yet. My sister found it weird that a 24 year old woman wanted to be friends with a 16 year old, so they had a talk. M said she didn't want to risk her friendship with my sister and that she'd only hang out with our brother if my sister was present. Well, a few days later, my brother tells our grandma that he is going to the pool and will be a while. He then rushes out the door. My husband went to do laundry about 10 minutes after my brother left where he saw M's car pull up. She got out and hung out at the pool with my brother and my sister was nowhere in sight, so I texted my sister and asked where she was. She said she was with another friend and M never told her she was going to hang out with our brother. When my sister addresses M, she claims that our brother told her that he messaged my sister and she was okay with it. My brother claimed he never told her that, and he didn't even know about their agreement that my sister was to be present. M is also a mom and her baby's dad was in jail. He just got out. However, she told my brother that he wouldn't be out for another month. Again, not true. Would this be considered grooming? Because this whole thing is inappropriate to me and the fact she and my brother started sneaking around to see each other is a red flag.