car seat safety.. don't know what to say?

So I have this friend that we will call Jane. She has 3 small children. One Just started school and the other two are younger. The other day I see

n a picture she posted a picture of her son and the only thing she had buckled in the picture was the chest clip. One of his straps was off his shoulder and twisted down at the bottom. I assumed that she took the picture before having him strapped completely in and the straps fixed, so I didn't say anything. Yesterday she posts a picture of her daughter on facebook with a caption of something along the lines of "sis holding on to her food so it don't fly out the window." Her straps were hanging off her shoulders, the chest clip wasnt on her chest, but her belly. The straps were twisted there also. I texted her and asked of I could talk to,her about something without offending her. she said sure, so this is what I said and what she said back to me, but car seats are designed to hold small children babies and so on.. so,I don't even know what to say to her without her feeling like I'm attacking her, but the safety of her kids while,in the car is what I'm worried about.