Do you mean the British Army, or the British Indian Army? If the latter, I suspect he would have had difficulty getting in. We could spend weeks talking about the complexities of Indian castes as filtered through British recruitment doctrines, but basically the army had always been more keen on farmers than merchants and lawyers and was moving away from upper-caste Hindus towards Sikhs, Gurkhas and Rajputs. This would tend to rule him out.
The former would have been more interesting. There wasn't a formal colour bar at this point, but I'm not aware of anybody from an ethnic minority ever actually trying to join. The first instance I know about was James Francis Durham, a Sudanese orphan adopted by the Durham Light Infantry who eventually joined the regiment and married the quartermaster sergeant's daughter. That's not to say there weren't previous ethnic minority soldiers, or alternatively that others tried and were rejected. However, I suspect the majority of recruiting sergeants would have turned him down not just on the grounds of his race but also his build, education and vegetarianism.
An even more interesting potential is for him to join a Rifle Volunteer Corps while in England. We know that these units accepted ethnic minority soldiers, because during the 1885 Russian invasion scare there were petitions to set up Indian volunteer corps from Indians who had served as British volunteers while studying in the UK. It's possible he might have joined one for social reasons- the 14th Middlesex (Inns of Court) RVC, for instance- and been persuaded away from a path of strict non-violence.