Thanks for the query to H.C.M. Forum.
High level of White blood cells may be due to any acute or chronic infection , severity depend upon the nature of causative pathogens ( bacteria, virus ).
Since you mentioned that several times he got pneumonia
If several times ( pneumonia ) , causative organisms were same or different , please mention.
Upload the X RAY
over this site along blood reports.
History which you mentioned in query is ambiguous , so attach all reports.