I don’t see a death for Andrew 1864 – 1876 so I would assume he died before 1864. In that case there’s probably no record, unless perhaps he died in the workhouse. According to this link, Castlederg Workhouse has death records from 1841 – 1934. They are in PRONI in Belfast. They are not on-line.
If the family isn’t in Griffiths it’s likely because they were either itinerant, lodging with another family or staying in a property of too low a value to be listed.
I had a look for other Norr(e)y marriages in Ireland 1864 - 1890 with father Andrew but didn’t see any.