To panic about toddler in booster seat

[FirstTicket]

DS (3) dad has just bought him an ordinary booster seat (backless). We aren’t together so I have zero control over knowing when he’s using it. He said that he’d just “bought it to keep til he’s older” after I told him he’s far too young to be out of a car seat.

But recently sent me a photo of him in it. I said again, he’s not meant to be in them. He’s told me it’s “just this one time”. Now I’m having panic attacks because any information I give him he just thinks I’m being silly and dramatic and won’t listen

He’s had crashes before and isn’t the best driver so I’ve always worried about DS in the car to begin with. I just don’t know what to do? If anything happened I would never forgive him

AIBU and overdramatic? DS is precious rainbow baby so I do get worried

He should be in a highbacked booster at the very least and if he's under 15kg he needs to still have a harness. Booster cushions arent really for that age group. What weight is he? Depending which seat it is it may have a minimum weight of 22kg.

Isn't there a legal obligation to have the age appropriate car seat? You could point out it's not just your individual concern but the law.

www.childcarseats.org.uk/types-of-seat/booster-cushions/

These are generally for over 6's

I’d probably be worried too, to be honest. Is DS definitely too short to be in it? My 3 yr old is pretty tall and graduated to a booster when she was 3 (nearly 4).
“Just once” isn’t a good reason to put your child in a dangerous situation, this would definitely bother me! YANBU.

Oh just seen it’s a backless booster - DEFINITELY not ok! My 3-yr-old only went up to a high backed one!

Been there OP- it's terrifying when you can't trust the NRP to take correct steps to keep your child safe. Is there any point in trying again to reason with him?