Finding information on the parents of John will be very difficult.
The surname Boyle is extremly common in Templecrone parish.
Like most of Co. Donegal, the Catholic church records for the area around Templecrone parish do not start until the 1860s-1870s.
I also looked at the 1857 Griffiths Valuation head of household listing for Templecrone and there were over 20 Patrick Boyle entries. http://www.failteromhat.com/griffiths/donegal/templecrone.htm
Have you looked for an obituary for John or his brothers which might show a townland?