Interestigly enough there is a citation in NARA, which appears to give his wife's name.It reads as follows:
SIMS, John Peek, Lieutenant (jg) USNR. Wife, Mrs. Audell Elizabeth Sims, Box 144 Mineola.(Wood County, TX)
One may wonder why his effects were returned to the mother rather than the wife.She may have remarried by the time the effects were returned at which point the Govt. gives responsibility to the nearest blood relation.