In Lady in White (1988) the killer, a serial killer of girls, drops his class ring in the school cloakroom while in rthe act of murdering Melissa. The hero Frankie, when locked in the cloakroom as a prank, witnesses a ghostly re-enactment of the murder and finds the ring when he returns and opens a vent.
No grandpa trying to kill himself, and it's the ghost of the killer seeking the ring not the victim. Doesn't really sound like your movie but check it out - https://www.imdb.com/title/tt0095484/?ref_=ttpl_pl_tt