I would suggest you stop the crating immediately. There is a reason for his not wanting to get into it anymore. One possibility is an orthopedic problem, either injury or arthritis or both.

Instead of crating him, confine him behind a baby gate, or even a closed door, when you would otherwise crate him. Make sure the area is cool enough and he has water, chew toys, and a comfortable sleeping surface.

And have him checked out by the veterinarian. This could be a chance to catch something early and make a huge difference in his future health.
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Kathy Diamond Davis, author, "Therapy Dogs: Training Your Dog to Reach Others," 2nd edition, and the free Canine Behavior Series articles at http://www.veterinarypartner.com/Content.plx?P=SRC&S=1&SourceID=47