It doesn't mean anything even if bodies were found. These were not wealthy schools, they ran on a shoestring budget, and people often died in youth due to disease at that time. When somebody died, they'd get a wooden cross, and that doesn't last forever.
This idea that there were being murdered at these schools, I think is largely unfounded. Abortion didn't exist, the natives were being forcibly "de-savaged", birth control wasn't around. Entirely different time.
https://www.westernstandard.news/news/no-bodies-found-after-spending-8-million-searching-for-bodies-at-kamloops-residential-school/54429