Marg,
First, the John Gelling in the will died in June 1822
Son Thomas presented the will in July 1822.

Braddan Burial Records
John Gelling 80 buried 2 Jun 1822

The John Gelling 89 Ballamillagh buried 31 Jul 1829 seems to have been md Margaret Quilliam
Burial Record Braddan
John Gelling 89 Ballamillagh 31 Jul 1829
Margaret Gelling Ballamillagh als Quilliam 11 May 1822

I'm finding that I'm needing to try to figure out the various John Gellings to see what I have and don't have.

The John who d in 1822 of Ballacaine does not appear to have an MI but to tell you the truth I've been scouting this out off and on all day and my mind is rather like jello at this point.

I never dreamed there were so many Gellings!!
Hopefully, some others will pitch in and help us.

Regards,
Donna