I can see Joseph was an Army Pensioner before he re-enlisted in the Depot Band at Ashton, aged 47. He was discharged with chronic bronchitis aggravated by his service. While this must have made hime surceptible to the pneumonia, I doubt CWGC would accept his death was proven to be related to his service. Glad he's commemorated here though.
Checking with IFCP to see if related conditions are worthy.
Tim
IFCP say "consequential conditions are not usually accepted. It has to be a direct cause and effect....The reasoning would be that most men suffered debilitating conditions that could be have been argued to have caused conditions in which any number of illnesses could take root. There would almost be no separating any man who served and later died."
EDIT IFCP 17/12/19