Might be anecdotal, but I had a cat all my childhood, then moved to university. when I returned home after uni i became allergic to the cat. I do think that you can build up a resistance to it, and now I have my own cat and am fine again. If my eyes become itchy I wash my hands and face with cold water and that makes it go away.
Having said that it might be easier to get rid of the cat sooner rather than later, before your son becomes too attached
Might be anecdotal, but I had a cat all my childhood, then moved to university. when I returned home after uni i became allergic to the cat. I do think that you can build up a resistance to it, and now I have my own cat and am fine again. If my eyes become itchy I wash my hands and face with cold water and that makes it go away.
Having said that it might be easier to get rid of the cat sooner rather than later, before your son becomes too attached