Yes, I've seen that film @
Discombobulated. Absolutely epic film of survival against the odds. Yes, the 'Brown Girl In The Rain' song, wow. You're right, in that instance having a song going round and round in his head, had a certain survival value. Amazing film all right. Herculean perseverance.
Incidentally, the only tool I personally use with any semblance of positive effect against repetitive thoughts, is
mindfulness. I'm sure you've heard of it or even utilize it.