Help save my dog

So this week we found out my dog Thor tore his ACL in his back leg. The surgery cost is more then my family can afford and my parents are talking about quality of life and putting him down. We're aren't ones to ask for help but I would really like to keep my dog alive. He is only five and still has much to teach us. He is always friendly and happy and loves playing with our kids. Right now he is in a bit of a pain and is sad because he doesn't get to go on the walks he is used to going on. I'd like to be able to keep him around and take him on more walks and see his puppy smile again! Thank you for reading this. God bless.