Preece Family Tree

His son David John's first marriage certificate of 21 Apr 1845 shows a father's occupation of "shoemaker" and doesn't say "deceased", so it is a reasonable assumption (but not proven) that he was alive on that date.

He is not the William John who died in Q3 1849 in Merthyr Tydfil, as that William was a collier. There are no other obvious candidates for the death of a William John who would be of the right age to be David John's father in either Merthyr Tydfil or Cardigan districts before 1858, suggesting that either the death was not registered (including potentially that he died before 1837), or that he died somewhere unexpected, or that he was significantly older than would be expected of David's father.