Did Billy Graham believe in the Flying Spaghetti Monster?

Yes, he did because once when he was eating at an Italian eatery an angry diner threw a plate of spaghetti which hit him in the face; the diner claimed they were under the control of the will of the Flying Spaghetti Monster which then caused Graham to perform an exorcism and label the FSM another manifestation of Satan.
True story, Hannity covered it on Fox News, which is the only real news.

No man it was the Invisible Pink Unicorn!

Sometimes?

Alas, no. He is therefore suffering in a pot of rapidly boiling salted water for eternity. Ramen!

who knows what he believed in

Only idiots and angry atheists believe in FSM.