Black mold

Okay , so here it goes . I loved in an apartment for.two years with my husband and two young children . My daughter is six , and our son just turned two in May . With that being say our son was extremely sick constantly for the first 7 months with respiratory issues. At eleven months old he got admitted to the ICU for bacterial pneumonia , once we were released three days later he has to start breathing treatments with a nebulizer four time a day every day until he was better . Well better never came , we visited the doctor 38 times within a 15 month time span for strictly respiratory problems . He was then diagnosed with reactive air way disease , allergy indices asthma and bronchitis. They asked us if we had mold.in our home . We kept saying no , because at the time we had no idea . Time goes on , more dr visits , more breathing treatments , er visits and antibiotics for weeks . Well eventually we find black mold start appearing through the paint around window seal and tell our landlord . He tells us he will take care of it . Time goes on then he starts harassing us for.irrelevant subjects and threatens to evict us . Me being extremely stressed and exhausted I take his deal to move out in two weeks and leave . Well the day we left we found a huge amount of black mold ( I was totally freaked ) . Now with that being said , with our son being damaged am I rightfully allowed to start a lawsuit knowing what I know now about it ? I have been out of the apartment for 5 months , son is still having respiratory problems but not nearly as severe . Can I rightfully so sue him for the time we were there and being the cause of his bad health while we were there