With regards to the Silver War Badge. It was instigated during the 1st WW and was not issued prior to this period. As for his age and service, the oldest that I have found recorded for someone serving during the 1st WW was 68 (although the person concerned had lobbyed his MP so that he could serve and this one instance would have been exceptional) however there were men who served in the forces well into their fifties. If you have a subscription to either the two main sites that deal with family history you should be able to search the SWB Roll that they hold to see if he is on there.
OR.