Hi and thanks for caring for this adult bun.
The first thing we check when someone complains of being allergic to the “rabbit” is testing if it is the rabbit, or the hay and straw the bunny may have. This is often the case and it is the poor bunny who gets the blame.

If you are with the bunny most of the day in this other appartment and the bunny is safe overnight, i wouldnt worry about leaving it, rather than moving it each evening.
Or you cooould get a sleeping bag….

It’s fine to leave him alone at night, my bun got used to it pretty fast (he lives one floor above my bedroom). You could attach a pen to his cage so that he has some space to safely exercise and lounge while you’re gone, he won’t mind as long as you spend some quality time with him every day!

As for allergies, yeah it’s probably the hay. Unless your bun is a pure angora or similar, since angora fur is pretty fine and can irritate the nostrils (I am sensitive to angora myself). If you want to give a go at keeping him in the family home do make sure his hay is contained in a hay box, vacuum/sweep frequently and brush him to keep the finer hair out of the air and store the big hay bag in a sealed box or in your office

I would assume it is the hay. I am allergic to all furry animals under the sun and am not allergic at all to my bun!

I do have to be careful about hay, I am allergic to timmothy hay. Orchard grass or Oat hay would be good things to try to avoid allergies!

We have recently moved our bunny from the garage to the house, our little Stewart is a great bunny. But u feel like he is waiting to use his living room litter box instead of his cage box when it’s cage time. As soon as I open his cage he runs right to the box, and dumps his box in his cage. Should I worry about this? I’m new here so pleas forgive if I’ve done this wrong!