Car seat and coat safety

Ok guys, what are your thoughts on this & what do you do for your little ones during the winter? Do you leave the coat on or off? I have an almost 2 year old so using a car seat canopy isn’t an option. I tried explaining to my mom that you’re supposed to take the coat off instead of adjusting the seat belt straps with the coat on bc it’s dangerous but she thinks idk what I’m talking about 🙄 and it’s just too much to go through.😐 when it’s comes to my sons safety I’ll do whatever i need to but i feel like when he’s with her, she won’t take the same safety steps as me