Lydia H Watson and her cousin John S Watson

In 1857 Lydia, youngest child of Asa Watson and Ede Tennessee Watson, was born in Mississippi. She was listed in their household in the 1860 census as Lydia age 2. She was found twice in the 1870 census, on two different dates and in two different households.  In June she was listed, along with her sisters Julia and Tennie, in the household of 65 year old Mary Hand. Wondering who Mary Hand was and how she was connected with this family. (No relationships were included in that census). A few months later, in September, she was again listed with her parents and siblings, but as Olivia.

In 1878 Lydia married her 1st cousin John S. Watson (son of her father's brother Rufus) and in the following year, at age 21, she died following the birth and loss of their unnamed son. John, born in Mississippi in 1853, was recorded in the 1880 and 1900 census as a widower and farmer.  He was not found again, nor have I found a death or burial record for him. What happened to John? I assumed he would have been buried in the Hawkins Cemetery of Clay County with Lydia and his parents.