We don't know that Charles Young father of Sidney served in the Boer War.
We know that Sidney's parents were registered in 1909 as Charles Young, and Emily, nee Wheeler.
We know that there was a Charles Young who married an Emily Wheeler in Liverpool 5 years after Sidney's birth in Bath, and that he was a West Lancs reservist who appears to have had a previous engagement in the army before signing up for the Special Reserve in August 1914. We don't know for sure that this is the same couple as Sidney's parents. Charles's age is wrong when compared with his death registration; the civilian occupation (general labourer) is wrong when compared to children's birth certificates; none of the children are mentioned in the army papers that we can find