marries younger SIL

Story details as I recall:

young man marries/becomes engaged

I believe that the wife/fiancee comes from affluent family

wife/fiancee is involved in an accident, however, before she dies, she asks her younger sister to take care of husband/fiance

husband/fiance and younger sister eventually marry

Thanks for your help,

Jarhead0311

I finally found it.

https://www.literotica.com/s/the-light-of-dawn-1