Silmarillion-movie?

[Galin]

Originally Posted by William Cloud Hicklin

The idea will also have to wait in 2043, when JRRT's copyright expires; or, conceivably 70 years after Christopher dies, since h is quite arguably a co-author of the Silmarillion.

I was wondering, is this unknown? Meaning, does anyone know if the 70 year detail pertains to Christopher Tolkien or not?

I would think WCH would know if anyone knew, so does this have to be decided by a court or something (if CJRT can be considered as author)?