I'll look at the will next time I'm at the library. It looks as though Olive may have been his only child, or at least the only one with surviving children, since everyone named (except his nephew) is her family.
John T. was Olive's husband, and John M., Gardner, and Mariah were their three surviving children. John M. was my great-great-grandfather, and the first surveyor of Amador County, CA. Gardner was the grandfather of Bill Wilson, the founder of AA.