My Husband Is 74, Diagnosed With Bone Marrow Cancer In

My husband is 74, diagnosed with bone marrow cancer in Sep; had 3 rounds of chemo late 2015. He has a persistent cough especially late in afternoon/evening. Had been in ant out of hospital for bacterial infections - unable to find source of infections. Now has this persistent cough late in afternoon sometimes accompanied by persistent cough. Usually accompanied by coldness/chills - but sometimes does not have fever.