Hello.
My connection is only a very distant sideways one through a number of marriages, certainly no blood ties, but he is in my tree (albeit at the end of a very long branch!)
There is a record for him on Ancestry (WW1 Medal Rolls Index Cards) showing that he was in the British Army from 26.3.1915 to 17.10.1921. His forwarding address on leaving the army was in South Africa.
This morning I was at the National Archives in Kew. He is recorded in their file WO/338 which gives a further file reference specific to him of P/83539. Unfortunately, the P prefix signifies that his records remain with the Ministry of Defence so are not available to view at Kew. I believe it is possible to obtain the records from the MoD but only if you are the next of kin. You may wish to pursue this. Hope this helps and let me know how you get on.