Asthma again...?

I was glad because for two months he was okay. He's growing and strong. In other word, very healthy. No more asthma attacked. Unfortunately, it started the other day, he has this mild cough and sneezing. And now I think it's asthma again. Oh I really hate to see him having hard time coughing and breathing. I hate to think of all the triggers. Hot summer, rabbit fur, and eating too much sweets? We go swimming one time a week. My second child also is now not so well. I noticed that he has low energy this past few days after he had fever. He is under cough medication. It's an agony to see your family sick. I'm very upset to think that this rabbit that we had temporarily causes everything. I'm just hoping my friend will be well and pick her rabbit soon. We're really not used with furry pets because of my family allergies. My family's health is at risk the more this bunny stays long in us. He's an adorable rabbit, we love to have him because the kids are happy. But we can't sacrifice their health just to have furry friends.
Oh God, how can I tell my friend that I need her rabbit out in my home now. I'm so agitated.