Re: Thomas McGrew Ireland>SC>KY
Thomas was most likily born in Pennsylvania. He says as much in his pension application in 1832. Fred Rose transcribed part of it for his tree on Rootsweb
The images are available on Ancestry.com
Elizabeth Mary Walsh, Thomas's second wife was still alive as she also added her recollections. Margaret Curry apparently died in 1776 and per thier account Thomas and Elizabeth were married when he went off to serve.
Elizabeth was likily born about 1858.John may have been born abt 1806 (a bit of a late birth!) The family moved to KY about 1807. I find a reference for John Marrying Sarah in KY on 13 Jul 1828 (no source).
1830 census for Calloway county shows a John H McGrew 20-30 with a female 15-20, no children
Also in Calloway is Thomas (with apparently Elizabeth) and William (alone)
Hope this helps