Is Difficulty In Breathing And Bubbly Phlegm Sign Of Histoplasmosis?

my father is 75 yrs old and has been in good health till about a year ago. He has had a hard time getting his breath and is spitting and coughing up clear bubbly phlem constantly. As far as we know he has a healthy heart, but he has worked trapping starling birds for the past 5 years and almost always without a mask, could there be a connection? Hystoplasmosis? thank you , bonnie