Hello Anne,
Okay, well Henry May was into his 30's when his was discharged so you can forget about him.
Boy's could and often did join the army, quite openly and not just in a fraudulent manner, although, this latter was brushed under the carpet a great deal, the living standards of the population were just so poor, that if you had a young man come before you, who was very keen to join and looked the part, then a blind eye was often turned.
Don't forget, it was rather differant than today and you did not need to show a birth certificate, all you had to do was pass a medical examination and so many did not and indeed could not.
It was a completely differing situation in those days, for example, if you lived in Ashton under Lyne, you might walk to Hartshead on a nice warm sunny day and then pop into the "Heroe's of Waterloo" public house for a gill or two of gin or rum.
Then instead of just going back home, you could well find yourself going across the road to Ashton Barracks and before you knew where you were, you could end up in the "Receiving Room" actually being given a bed-cot, then being woken at 06.00am the following day, taken before a doctor and being issued uniform, being sent to the Training Company after breakfast.
It really could be as easy as that, you just went out for a walk and in less than twenty four hours you were serving Queen Victoria, a far cry from the way things are done today, it takes about a year these days, to do what was so often done in just a few hours!
So really, the army was always very keen to get all it could, a 14 year old could join, with the rank of "boy" and under certain circumstances, he might find himself out on campaign a very short time later, so not at all unusual really.
I always smile at the term granddad when it is used on here, as the war was concluded one hundred and twelve years ago, moreover, family stories often end up rather distorted over so many years, notwithstanding, you need to find out what his name was before you can even think about taking this matter any further, May, is a very common name and there are lots of possibles, although, if you are saying that he was a casualty, the field becomes rather narrower.
Anyway, I wish you bon chance,
Regards Frank Kelley