Okay, thanks for the refresher. Yeah it really does look like he is Thomas Archibald Grimason. I have a feeling the weaver Thomas that is father of Sarah Thorton is the same Thomas your looking for but more proof is required.
I thought I could find a death for Thomas in Ireland or Scotland as well but no go. I checked the USA and nothing interesting for an Archibald or Thomas Grimason (under various spellings).
I have the feeling that spinster Sarah Grimason is sister of Thomas and that is why he had a daughter named Sarah. Now if I could just prove it
I think it's worth looking into whether this Thomas Grimason mentioned below is the right one. It has a few things going for it. He's a weaver , right name , daughter is purported to be born in Tandragee. Wife's name is correct ... Elizabeth.
If it is the same Thomas Grimason then Elizabeth would be Elizabeth Holmes (according to the links). This daughter Elizabeth Grimason married a Freeman in Australia and appears in these write ups:
https://www.eurekapedia.org/Elizabeth_Freemanhttps://www.ballaratcemeteries.com.au/events-and-history/women-who-shaped-and-built-ballarat/freeman-elizabeth/It's quite possible that your William Grimason is son of the same couple above and brother to Elizabeth mentioned (and possibly Sarah Thorton).
Of course it's quite possible this is a different weaver named Thomas Grimason...
Worth checking into I think.