I just found out

Sadly, yes

Did they have a reason for deleting?
Did they make a image where they said goodbye?

i unfortunately didn't see an image where he said goodbye, or a reason
he just thanos snapped his account without warning
there was a theory site mods did it but that was disproven if i'm not wrong

He was forced to delete by his parents according to kraber

I saw that just now

their parent went thru their computer and the said they needed to get off

dang

I heard that Asriel. did it because he wanted to do something else with it's life.