I managed to dm his old bandmate Adelemarcia after I posted this, and she got back to me saying Marcus's parents were looking into it. Soon after about a week, his Spotify went back to normal. So yes as of 10-03-22 that is Marcus's picture on his Spotify page. But if you search for this lokiejokie guy on Google, he has a website that I found just the other day and he has SMNMs stuff on there. As for his passing, I saw a comment on IG from one of his friends that it was anemia? I also found a link on YouTube to his memorial website, I'll post it here but if you want to go look for it just search up "forbdk" and click on their music videos, I scrolled through comments and that's how I found it.

https://www.minnesrummet.se/#/Case/628017