First of all, do glad to hear Axel has is sparkle back and is his goofy fun lpving self.

I know it's  upsetting   for him (and you) not to be able to reclaim his nighttime sleeping time with you.  

Yeah, also curious if you have tried any type of harness support yet for going up?  If not, maybe start off with him jist wearing it for a little bit and not have it associated with stairs, but rather something  pawsitive.  If he likes carrides, or trips for drive thru cheeseburgers, he can swear ot then.  One of my dog likes carrides and I use a harness.  If  I get anywhere near his harness he associates that with fun things and gets wild and crazy happy.

Just to piggyback on what Jerry said, it does sound like a fear and confidence  thing.  Although my Happy Hannah was a rear legger, she stumbled once on one of her first tries going up...and that was pretty much it.   Too fearful after that.

 Now, is there anywhere you can go that has a few stairs.....maybe a friends house that he likes with porch stairs, something like that.   If you can get him to associate  something  grest with stairs to the point he doesn't  even focus on stairs.,he just sails up them.

One other though.  Is there a doggy friend, or hooman friend, he really likes you could bring to the house,.  Have the hooman in a  Happy   and confident state as they all head up the stairs for some chicken or whatever.  Not explaining it very well, but you get my point.

And what is your energy like now when you try and get him up the stairs?  Happy and confident  or frustrated and feeling defeated.? Axel is so bonded to you and your energy becomes his.

Anyway, just throwing   all this out in the FWIW And it is still early..

Keep us posted.  Again, do glad Axel is back to bring Axel.

Hugs

Sally and Alumni Happy Hannah and Merry Myrtle and Frankie too!