Usually after the Death Registrations one goes searching for any obituaries, for they most often list the survivors' names and in your case, hopefully, the married surnames of the daughters. Do you have any obits yet? At the BCArchives search are there are Probate/Estate Files for:
Call Number: GR-1415 Title: Vancouver Supreme Court probate/estate files 1893-1941. Reel no. B08732Tourcotte, Elizabeth FrancesProbate No. P - 11028.
There is also one for Tourcotte, Joseph Paul Michaelwho died in 1987, aged 36. Any interest in him?
We also have Herres, Mathias' Probated Will. Names of beneficieries could appear here.
There are of course two Death Registrations: William Calvin Tourcotte (d.1974 55years) and William Tourcotte (d.1982 87years). Which one is yours?