This song is beautiful and I can't figure it out for the life of me. I've even tried watching live version to try and pick it up. I'll put both the live version to show how we plays and the studio version for quality.

Studio Version

Live Version

In the live version you can see what he's playing at around 4:53.

The first is an F chord. he uses his Thumb for the 6th string.
1 3 3 2 0 0

the second chord is an C
X 3 2 0 1 0
Metal is the Law