I don't think I will be able to help, but to save the other responders the trouble -
Do you know where he died? It will probably help find the burial place. Or where others in the family are buried, if in NI.
The death record will be available soon - 50 years after the date - at
https://geni.nidirect.gov.uk/.
The index of the record will be free - at least they always have been.
I don't know the time limits for the NI will index - someone else might.