Getting my rescue over his fears Discussions

After losing all three of my dachshunds over a period of years I needed a companion dog who needed a home.
I found Cobber as a private rescue. All indications are that he was dumped.
Cobber is a young Blue Heeler, fully intact.
He is loving to everyone, very playful and accepting of all the neighbor dogs. He loves being in our huge back yard and doesn't try to get out of the fence.
He is obedient only when his desires align with mine.
Our big issue is that he is terrified of a leash. So far he has destroyed one leash and several soft cotton ropes I let him drag.
He's too big for me to pick up at about 45 lbs.
I need to get him checked at my awesome vets. I want to take him for play dates and grooming.
I'm on a very tight budget but I'm considering getting him a companion that may help show him leashes can be ok, and who will play with him in ways I cannot. I welcome your stories, thoughts and advice.