Having cleaned houses for years, I can tell you that Hepa filters don't do much good, at least according to the people that I cleaned for. Plus I always had cat hair and dander on me no matter what and I'd bring that into their homes as well. An air purifier might be your best bet but your boyfriend must be careful of taking OTC meds for allergies. When my son became ill a year ago and experienced temporary paralysis, one of the drs. told him that OTC meds can cause such things. He showed my son a list of them and it was as long as his arm. He was researching Claritin at the time my son went to the emergency room. To take those meds on a daily basis is a dangerous thing. I sure hope you find a solution. This must be tough for you.