He's his best man :)

^right! :P they're like father and son, it's probably not considered appropriate in real life but as far as the crazy world of glee goes it's cute. :)

And this is why...

1) Will saw something in Finn and got him to join New Directions (Pilot).
2) Will was there for Finn when he found out that Quinn's baby could possibly be his (Preggers), and then took him to the ultrasound (Throwdown).
3. Will tried to get Finn back into New Directions, although Finn would want to know why he has to be the bigger man in the situation between him and Puck (Sectionals).
4. Will tried to get Finn back on the football team after a feud between Finn and Coach Beiste (Audition).
5. Will tried to change up Finn's punishment after he walked down the hall in his Rocky Horror costume (Rocky Horror Glee Show).
6. Will encouraged Finn during Booty Camp (I Am Unicorn).
7. Finn is excited about Will marrying Emma, and goes to Zales with him to look for rings. He also offers to be Will's best man. During the conversation about the army, Will was concerned about him (Yes/No).
8. Will is worried for him, along with Santana and Mercedes, about his future, and helped him choose schools, witht the help of Emma and Rachel. After finding out that Finn threw the brochures away, Will tells him to dream and makes him watch "Saturday Night Fever" after Finn says he's not qualified for anything after high school (Saturday Night Glee-ver).

If that's not proof on the fact that they seem close, I don't know what is.

no question.

It's really disturbing how close they are.

Duh

Then Quinn

definitely finn
then if i had to pick a second id say kurt