I hope so very much that he settles in quickly and well. I can only imagine how gutted you feel, but it is good that YOU got to choose his next home, because you know him as no one else does. I do hope his new mama is well informed on keeping dogs safe in new surroundings - particularly with moving him twice in two weeks - so he doesn't decide to try to find his own way home in an unguarded moment. Not to give you another thing to stress over, but I've done too many searches for newly rehomed dogs and/or dogs on vacation out of their familiar area. If this wasn't one of the things you discussed with her, and if you want an article I wrote on the subject, I'm happy to send you a copy of it that you could forward to her.
Thinking of you and of Zeke, and feeling positive about his new placement. Having rescued many dogs, I'm always amazed how they settle in. Sadie took the longest, at three months or more before she stopped 'looking' for her people, and Maggie is taking quite a while too, but most settled within a week or so. And once Sadie accepted that I was her new mama, she just moved right on with her life and never looked back.