Have to say the original post here has me quite confused.
Joseph Doak Sr died 1898 per PRONI and his will mentions Joseph (Sarah) as one of his executors. There is no civil record of the death on familysearch to give the age.
There's a death registered in Lisburn in Jan - Mar 1898 for Joseph Wilson Doake, b 1823, Volume 1, page 560. Is that your Joseph?
I searched PRONI Wills and can't find a record of a Joseph Doak who died in 1898 although I did find Valentine Doak "late of Ballynagarrick County Down Pensioner who died 10 October 1898." Will mentions wife Priscilla, son James, daughters Margaret Elizabeth* & Lily Bella, son Alexander (America).
I can not find a marriage civil record for Alex or for Sarah or for Joseph marrying a Sarah.
Civil registration index lists a marriage- Joseph Doak, Jan./Mar.1878 Banbridge registration district, volume 1 page 243