What if monsters have longer lifespans than humans?
I guess, big sibling Frisk would try to comfort Papyrus to be strong, be big and to keep on being happy after their death. They are proud that their baby brothers turned to be awesome people and they hope that the skeleton brothers will be ok without them.
Papyrus would be visually more devastated than Sans about Frisk’s burial. Sans tries to look “stronger”, but in the end there are still tears. In the end, they lost a huge part of their little family.
I was trying to go to bed at like 2am the other day and somehow ended up thinking to myself “what if Frisk just brought back an old person after they left the barrier” cause nobody ever said you had to murder someone to get their soul which led to this nonsense
and here’s a bonus because I’m an dummy and forgot the beginning of the phone call: