Screaming baby

I need help , I’m moving and going to be taking a five or six hour drive to get to where I need to be. My son (five months) hates the car seat. Specifically when he gets tired he starts screaming and he won’t stop screaming until either we can get him out or he passes out. I hate seeing him scream himself for twenty minutes to sleep, makes me feel terrible and especially when he doesn’t breathe while screaming. Does anyone have any suggestions on what to do? I’ve tried his favorite songs etc. doesn’t take a bottle or binky