In "The Vampire of the Village" by G. K. Chesterton, Father Brown was talking about an old parson and his son, saying:
‘I mean,’ said Father Brown, ‘that the son still speaks of his father in a hard unforgiving way; but he seems after all to have done more than his duty by him. I had a talk with the bank manager, and as we were inquiring in confidence into a serious crime, under authority from the police, he told me the facts. The old clergyman has retired from parish work; indeed, this was never actually his parish. Such of the populace, which is pretty pagan, as goes to church at all, goes to Dutton-Abbot, not a mile away. The old man has no private means, but his son is earning good money; and the old man is well looked after. He gave me some port of absolutely first-class vintage; I saw rows of dusty old bottles of it; and I left him sitting down to a little lunch quite recherche in an old-fashioned style. It must be done on the young man’s money.’
Can "at all" be used in a positive statement, and what does it mean here?