Your theory is very similar to mine - BaDIK gets more serious and darker with each season, like JK Rowling's books. In the first season, everything is light and fun, joining a fraternity, practical jokes, parties and a little drama with a love triangle.
The second season is the first serious challenge for the MC. A ruined mansion and the narrative is no longer so light. More sad moments, but still nothing terrible.
And in the Interlude, the first death during the gameplay and the funeral of Zoey grandma. Everything is darker and gloomier.
When that scary preview with Jill and MC came out, I hoped until the very end that it wasn't Neil - I was so attached to him as a character. Now everything seems to be in place. I agree that he won't die, most likely an accident. Repeating the plot "my friend/relative one is seriously sick" is a self-plagiarism of Acting Lessons and Liam's cancer.
I think that Neil got into a road accident with his van and got badly injured. I remember the end of Episode 8 when the windows were being changed. MC said to Neil, "Drive safely, dad" or "Be careful on the road." Something like this. Even then, a chill ran down my spine. I know DPC and how he loves tragic dramas.
And thanks for correcting me with the renders of the main menu. It's all my inattention, and I'm kind of not old
