I have multiple chemical sensitivity with multiple food problems too. Reading your post I just felt bad for you because I think you will ultimately have to move. Honestly, the toxic cleaners your father uses alone would just about kill me, never mind the stains and paints he uses to make furniture.
I think if you continue to stay there you will likely become worse, and it can progress to a whole new level. I am now at the point where I am sulphur/sulfite, histamine and salicylate intolerant, as well as dairy and gluten intolerant, and so my diet is horribly limited, that's how it can go sometimes..
I dont know anything about air purifiers. But, I can tell you that anything with coconunt in is very bad news for me as it is high in salicylates, this might be something or nothing, but I thought I would mention it.
Stopped smoking Jan 2013. Diagnosed Left sided UC, 8th Feb 2014.
Gluten, Dairy, Sulfite, Salicylate, and Histamine intolerant.
Had home FMT treatment in July 2016 to ward off reoccurrence of C DIfficile.
Taking Methotrexate 10mg weekly and on 10g of Prednisone at the moment, hoping it will work for me.