Sounds like you have been working hard with this.

Do you have an extendable lead, this shouldnt tangle.
Using an extendable lead for practice you should be able to take him near distractions then call him and if he ignores that give him a tug and call again.
if he tries to lie-down in protest, simply call him and turn and walk, he will learn that you are in charge and not him.

I am currently at this stage with my 16 week westie, she is happy to return for a treat, but if she is running toward another dog she doesn't want to listen. Thats not surprising considering her age but it cant become habit so I would never ever let her off the extendable lead until she is recalling under distraction conditions. Dogs are so smart at teaching themselves that it doesn't have to happen more than a couple of times for her to learn that she has control, and not me.

Good luck, he's lucky to have someone prepared to make so much effort

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