Although I'm certain that William is Patrick's son' I wanted you to have documentary proof.

The LiberVast/Assed entries for 1768 would show "Patrick Kelly - William his son" side by side. A horizontal line drawn through Patrick's name.
"The father is dead and his son as heir is entered according to Law"

A similar entry for William's death in 1790.

Do you knowq anybody on the Island that could look up the two dates for you?
Harry