Sadly, they just aren't ready until they are ready.
That was a generous offer you made, and even though it was declined, he can find recovery on his own if he really wants to. Salvation Army rehabs are very good and are free, NA, AA, and other support groups will welcome him when he makes the first move to walk in the door.
You did a wise thing by stepping away. Living in our recovery and their addiction at the same time just isn't possible...and the only recovery you can contol is your own.
My prayers go out for both of you, that a better path is in sight for each of you, even if the paths are not the same.
Hugs