I agree it is a sensitive subject but there are other ways of determining death aside from following up with next of kin as it is public record at least in the U.S.. Progression would presumably be known or at least be censored to the date of the last follow up without evidence of progression.
If I or a loved one had entered a trial, yes. One of the reasons to participate in a trial, other than the hope for getting an effective new treatment, is to help advance the state of treatment for those in the future. It helps make one’s death a little less pointless.
Small comfort when one is dying of cancer perhaps. I get what you’re saying. I’ve been there with two very close family members to the end.