It would be easier to help if you had given the parish for his will and for the marriage you mention, and also say where your information comes from. The Maughold parish register has a burial for William Goldsmith on April 3 1827 (not the 28th), but gives no age or other details.

The Maughold register also records the baptism of William the illegitimate son of William Goldsmith & Jane Kirmeen on 3 May 1795, but with no place name or other information.

If there were so many William Goldsmiths how do you know that this is the William who married Isabella Kermode in Maughold on 7 Mar 1818, other than that these three events took place in Maughold? Did the father's will name his son's wife, or his own? Have you seen other wills from this family? Are there MIs which link them together?

Can you post a transcript of the will(s) which might have more clues?

Sue