You don't have to rely on treats if you use them, just don't lure with them. That means have them in your pocket when you go on walks until this clears up. Don't use the treats to make him walk but if he chooses to walk every once in a while pop him a treat so he learns walking is good. praise alone works for very few dogs, honestly, kind words are not all that great especially when he gets them all the time or he would rather be doing something like playing with another dog. For instance if your dog was running towards another dog and you said come the dog would think "I could run back for a "good boy!!" and not get to play with this dog or I could ignore my owner and get to have a blast with that dog" perhaps not in such a complex thought process but something like that, and most dogs will choose play over happy voice. Super duper yummy treats on the other hand can be much more motivating.
Anyway that's my feeling on treats, I use them and the dog I train does not need them all the time because I don't ever show them to her when commanding her anyway, she has learned she might get a treat even if she does not see it. If i don't have treats she still listens
on the off chance she might get a reward and because it's somewhat of a habit now to do certain things when I say certain things. If I do not have a treat I still praise and/or find another method of rewarding (sometimes it's an immediate release from the command and I run with her because she likes that, I allow her to sniff something I think she'll like etc.).
When exactly does the dog stop walking? Many puppies who are growing cannot walk long distances, it is not good for their bones. So try and do short frequent walks not one or two long ones. if he does stop moving try to pretend to run from him (some will want to chase) if he does get up praise/treat and keep going. If he does not chase then simply wait for a few minutes and then try and verbally encourage him and rev him up.
The number one thing not to do is pull, dogs naturally resist pressure, if you push on a dogs side they lean (and if you move your hand away really fast they fall over
) if you push a dogs back to get him to sit most dogs will push back up unless you are physically stronger than them or you hurt them
. Same with trying to force them to lie down.
If you could be more specific as to when he stops it would help.