Hi Chelsea Pilot,
Forgive my lateness to the party, I've only seen this now. If interested in the Galway Militia, I recommend David Wilkins' article in the 1998 JGAHS. If you're having any difficulty getting access, just let me know.
Onto John, did you view John's records on FindMyPast? Did they provide any additional detail in terms of where he served? He was one of at least 32 from that parish who fought (and survived to discharge) in the British Army in the nineteenth century, though I cannot see any others from the 65th regiment.
S.