I don't think Obadiah and Annie Brooks had more than the single child, Thomas, born c.1902. At the 1911 census, Obadiah reports that they had only had 1 child, and no child is recorded with surname Chew and mother's maiden name Brooks between Sept 1911 and Obadiah's death in 1914.
I also don't know whether Thomas ever married; might he be the Thomas, though, who married Lily Bamber/Salisbury in Blackburn in 1920? Have not (yet) followed up the later fortunes of that couple.
Besides this Obadiah Chew, there was another Obadiah Chew from Blackburn by the way, born about 1794, died 1846; he married an Ann Robinson in Blackburn in 1817. In view of the name, I wonder whether he was related to the Henry Chew who was "your" Obadiah's grandfather.