He married Eliza Ward in Sunderland Durham England in 1936, but she remarried in 1944 stating she was widowed. However the Glasgow register of 1945 has Charles Brown Filshie living with his brother John and sister Margaret. No record of him after 1945.
I've looked for his death record on ScotlandsPeople and also in the UK death indexes, the CWGC register and deaths overseas. I've tried different spellings of the Filshie name, all returning negative results.