Yes the 1842 death may not be correct - unless Susanna died after the birth of Dixon, and George has a different mother ....?
The marriage of John Rylah (and
possibly Susanna Gibson) in 1841 would fit in with John still being at home with his parents, as the census was taken June 1841 ... and the marriage took place Sept 1/4.
It looks like a shotgun wedding with Dixon chr Dec 1841

Purchasing both boy's certificates would tell you who the parents are ...