Our family pet is an 8 year old Labradoodle, and he refuses to go on walks with anyone except my mom. He'll only go on walks with me if my mom isn't home or if she comes with us. If my mom is home, or not coming with us, he'll just sit down and stop until I bring him home. Sometimes I can't even get him out of the driveway. He does this to my mom too sometimes but not as often as he does to me. I've tried luring him with treats but that didn't work. He's been doing this since last year, but he's been to the vet since then and they say he's healthy.

So for 7 years he walked OK and now won't? Anything change in the home like a person coming or going? Any new pets or other changes? This sounds behavioral and he must be retrained.

There's nothing 'wrong' with him, I'll bet. He's being stubborn and has gotten away with it so far.
I was walking friends' 85 lb dog once and he glued himself to the sidewalk about a mile from their house, and I couldn't budge him. Finally a man drove by and yelled 'get up' in a deep baritone, and the dog jumped to his feet and home we went.
It's all about who the dog considers an alpha dog, and I definitely didn't have that stare them down, unswerving sense of command.

Welll.. since its been reported that he does this to mom as well, I would go with some type of back, knee or hip pain.

8 year old large breed dogs will have joint problems. Sometimes these big guys will hold back showing pain, so unless someone mentions it to the vet, the vet may not have found him to be painful anywhere.

I would also say he is being a jerk. Next time he does it.. grab him by his collar, slip the leash around his belly and hoist him up and move him forward. That's not the most comfortable way to be walked, so maybe a few times of being "heavy handed" he'll get the point and do it on his own.

I don't get why owners let their dogs call all the shots... *sigh* Not only does it make owning a dog un-enjoyable, it can become dangerous.