Ah -- it is great to hear how happy you are with Happy!
You have definately been a blessing to him and it is so nice that the blessing is returned.
For help with the walks -- invest in a coupler. It lets you walk them with one leash, attached to a ring with a swivel that then has two leashes on it. (Or you can get as many short ones as you need). It helps a lot and keeps from those tangled leashes when you have a separate one for each. Make sure you get the kind wiht the swivel -- it ensures no tangles as they can keep crossing each other but the coupler just swivels instead of wrapping around itself.