8 month old Careseat issue

My 8 month old just got switched to his big boy Careseat. With that being said he's 24lbs so we have the seat reclined to the suggested setting based off his weight. When he falls asleep in his Careseat his head dangles forward and it makes me uncomfortable. I've tried putting a blanket to see if it'll help keep his head up but he ends up leaning to the other side. I get worried about his poor neck and his breathing..is there anything you momma's do to fix this? We're driving from TX to CA next week so I'd definitely like to figure out a solution before then.