Advise booster car seat

My kids are older so it’s not an issue for me. My brother is now ready to pull the trigger , but he tried his booster car seat and that doesn’t fit.

Any model that could work ?

Thanks!

My kids are older so it’s not an issue for me. My brother is now ready to pull the trigger , but he tried his booster car seat and that doesn’t fit.

Any model that could work ?

Thanks!