I agree with admin, if the mattress is on the floor, I don't know of a reason to keep him off, unless it's just that you can't get it to the room where he's going to be.  If that's the case, the beds and blankets will be fine.  My experience with other dogs is the other dogs didn't seem to realize Roxy was going through anything.  That meant if they were coming to eat dinner and Roxy was going too slow, they just pushed right past her.  I don't remember her ever being knocked down, but she was definitely bumped into a wall on a couple occasions.  I almost had a heart attack!  But Roxy just kept going, she didn't let it trip her up.  I'm not sure, with the Dane's being so much taller if Alexander would have as much grace.  The elevated bowls are a must.  We took a bucket, turned it over, cut a hole, and used a bowl (with a lip) set into the hole.  You may need to get a tall bucket!

Good luck tonight.

Leslie

Today was the first day my dog Chloe (amped 8 days ago) was briefly reunited with her sister Rocket. They do tend to play alot even at the age of 9 (for both), so unfortunately we do have to keep them separated most of the time (since Chloe still has her staples in). We let Chloe have a 10 min, monitored reunion in the grassy backyard this morning, which is only because she has become much more secure using her new body. In this I mean standing, sitting, walking, and going to the bathroom with ease.  She did stumble a couple times trying to play with her sister, but since Chloe has gained strength in her remaining back leg from a week of recovery, she got right back up again no problem. I would just use your discretion based on your situation with your dogs because this just my situation with our dogs.

Also, we have a cat that Chloe usually gets along with very well, however she has been a bit "snarky" when he invades her living room space (where she is cooped up in all day with me). Otherwise, outside of her confinement she is fine with our cat. Hope this helps!

Best of luck to Alexander!