You may find it worthwhile to spend some time visiting The National Archives. It will be easiest for you to find information if you know which regiment he was in, but it is still possible for you to do so if you don't know.

The majority of records of men discharged to pension between 1760 and 1913 are preserved in the records series WO 97. These records are arranged into distinct collections according to date of discharge and in some cases unit.

Between 1760 and 1872 the records are arranged in two chronological ranges 1760-1854 and 1855-72, then by unit, and then name.

Between 1873 and 1882 the records are arranged by type of soldier (e.g. infantry, cavalry, artillery) and then in alphabetical order.

From 1883 to 1913 the records are arranged in alphabetical order in two chronological ranges 1883-1900 and 1900-13.

Soldiers' discharge papers, 1760-1913

Soldiers' pension records, 1702-1913

Muster rolls and pay lists, c1730-1898

British Army: Useful Sources for Tracing Soldiers