researching my grandfather and his family connections

I am researching the life and times of my grandfather John Sullivan (1871-1962). He was born in 1871 in the townland of Kilkeaveragh, in the parish of Killemlagh, to John and Hanora Sullivan on their small farm. His mother Hanora was also a Sullivan and came from Valentia. The 1901 census has her still living in house number 14. I dont know how and when she died and I know nothing else of his father. My grandfather left home in 1892 and joined the R.I.C. I have spent some time researching his subsequent history with some interesting success. However I know very little about any Kilkeaveragh family connections. I know that he had a sister (name?) who went to America, married a Foley(?) with connections in the Kilkeaveragh area but both of them were supposedly killed in a gas explosion, probably in New York. Apart from that, John Sullivan might as well have been born under a gooseberry bush! Did he have any other siblings or other near relatives? I have him living in the area for a few months (1914/15) although his service records show that he was never formally stationed in Kerry. (It was common R.I.C. practise to ensure that policemen were not allowed to serve in their native area). Why was he there? Was it connected to the farm/his mother?