There is a very, very extensive family tree online which gives as it's main source a family tree drawn up c1900 and includes Thomas Crawford and wife Phoebe Toppin (Topping?).
One thing of concern for any of the details I found online is the Will of Rev. James Dawson Crawford: Probate of the Will of The Reverend James Dawson Crawford late of 104 University-street Belfast Presbyterian Minister who died 5 October 1902 granted at Belfast to Mary Alice Crawford the Widow.
Will mentions sister Phebe,
sister Ann Jane Boles*, nephew Arthur Crawford Watt** (minister Free Church Cromie Scotland), brother Joseph Dawson Crawford DD (Liverpool), nephew John D Crawford (barrister, London).
* there is an Ann Boles in 1901 census that might be her but unfortunately it looks like her son Robert James Boles was born c1845 so her marriage is probably before the start of registration.
Probate of the Will of Anne Jane Boles late of Tomany County Monaghan Married Woman who died 18 April 1902 granted at Armagh to Samuel Boles the Husband and Robert J. Boles Farmers. Will mentions son Robert James
Ann Jane (c1823)
www.census.nationalarchives.ie/pages/1901/Monaghan/Aghabog/Tomany/1632836Robert James Bole (c1845)
www.census.nationalarchives.ie/pages/1911/Monaghan/Aghabog/Tomany/805811** wife Letitia's Will mentions her deceased sister Martha Watt so Arthur is likely Letitia's nephew.
James Dawson Crawford's marriage to Letitia in 1851, however, does show his father's name as John-
https://familysearch.org/pal:/MM9.1.1/FGCW-82F