Rose: The Vancouver Sun, Feb.10, 1982 obit for a Peter Mcewan (spelling is different from the same person's BC Death Registration, Peter Mcewen, 49, who died Feb. 6, 1982.) says he is survived by "wife, Elaine; son, Warren; daughters Debbie and Sharon and son-in-law Stewart; mother and 3 sisters". Stewart's surname is not given. The obit said a memorial service would take place in Maple Ridge, BC (east of Vancouver).
The same newspaper on Feb. 8, 1982 had a short account of Peter McEwen's body being recovered after his pleasure boat caught fire and was destroyed. His address was 5715 Jersey St. Burnaby BC, (eastern neighbour to Vancouver).
Sheila and Joy could be 2 of the 3 sisters that were mentioned in the obit. But the obit says the mother was still alive at this time, 1982. Therefore there is a problem with your info indicating the mother, Jean McEwen, had "died in the late 1970's in North Vancouver, BC".
From BC Death Registrations: A Jean Mcewen, 82, died in North Vancouver BC, Jun. 2, 1972, but her obit has no names you are looking for.
A Vernie Jean Mcewen, 81, died in New Westminster BC, Mar. 30, 1975. I found no obit in the Vancouver Sun, but there may well be one in a New Westminster (a suburb) newspaper.