Welcome to Ireland Reaching Out!
The RC church records for Holycross parish do not begin until 1835 so we won't be able to locate a baptismal record for James.
I checked the 1834 Tithe records for Holycross civil parish and there was one record of interest. A Lawrence Toohy in Cormackstown (Actually all 157 Tithe records was shown in Cormackstown). Looks like he has a little over 4 acres of land that he leased.
I also checked the 1850 Griffiths Valuation head of household listing for Holycross civil parish and there were four Tuohy/Twohy records. Not sure how these folks relate to James.
Also checked the 1901 census and found one Tuohy family.
You can James' story to our XO Chronicles site and possibly someone will see a connection https://www.irelandxo.com/ireland-xo/history-and-genealogy/ancestor-data...
Have you considered DNA testing?