I know what you're going through. My husband was allergic and I didn't care enough to get rid of them for him, but as soon as my son was allergic it was "you're outta here" So, there is an organization that takes in cats, puts them in foster care and adopts them out. You have to pay to have this done, but it was a small amount for my piece of mind. My cats were my babies before I had babies of my own and I needed to know they were going to be well taken care of.
The problem is, I can't remember the name of the organization. The only thing coming into my mind is St. Jude (obviously NOT right) So, let me think about it and look on-line to see if I can remember. I'll be in touch.