Car Sickness really bad

So I have an Australian Cattle dog named Tuso, 6 months old. Long story short we knew he gets car sickness the first day when we drove him home. Thick drool, vomiting. And its always been like that even for the shortest car rides. If its like a five minute drive it will just be drool, any longer he will puke. He recently got fixed. The last few days have been worse than ever, a 20 minute ride to a vet appointment he puked 3 times and puked a forth time walking outside of the car. The vet told me to try putting a blanket over the cage in the car and we did that but it doesn work, when i look online some say to leave the dog out of the cage which i havent tried yet. I havent tried benadryl either because i dont understand how to make that work and not have a drowsy dog when we get to the park. Its gotten so bad that he associates the car with getting sick and starts to drool before even getting in the car. Is this something that can get better over time since hes still a puppy, what can i do because it sucks that he gets sick every time I try to take him somewhere fun.