Hi
If your great granddad was from Co. Kerry then we should get in contact. I have laid out most of the lines here and have done some DNA testing to prove all North Kerry Brassils are in fact related. Some of these lines I can take definitively back into the mid 1700's.
The names of Robert, Daniel, and James are definitely ones that run in certain branches. Any townsland names in Co. Kerry that you may think are a possibility would also be helpful.
If you know John's wife's name with a maiden name, that would also be very helpful.
Bart