It’s terribly sad, but if someone is so determined, there really isn’t much that can be done, other than to help the family try to understand that they were in no way responsible and the deceased had made his or her own decision.
Years ago, an acquaintance’s son hanged himself over a girlfriend - he was 14, such a waste.
My friend’s step-son hanged himself after years of drug abuse and issues around his 7 year old son. He’d had multiple interventions and on-going treatment, but we agreed after the event, that it was always on the cards. His GF had done the same thing.