I did read the comment and it was worded weird which is why I wasn’t sure if they meant spent instead of spend. If she is supposed to be living there then it is unfortunate that she is unable to but I’m not sure why a minor would only live with their only living parent for 50% of the time and also did not see where they mentioned being a minor. The dad did make effort spending thousands on a filtering system and what sounds like hours deep cleaning the house in preparation compared to trying one pill and saying it’s a no. If OP is a minor then yes there should be more effort to make the home livable for her as well even if that means temporarily or permanently rehoming the cats, but if she is an adult and simply visits then I think she should be more open to trying other medication before the family tries to rehome the pets. Rehoming IMO should be a last resort because pets are a lifelong responsibility and should not be discarded at the first inconvenience. Again this is all more based on the actual living situation once that is cleared up more bc yes if she has that strong a reaction and is supposed to live there then getting shots possibly daily (idk) would be too much for a minor just to stay under her guardians care.