Another conifer question

A similar question to one I asked three years ago about a smaller conifer (which hasn’t recovered), but as I know very little of gardening it seems worth posting.

This tree belongs to my mother who’s in her 70s and loves her garden but doesn’t use the internet, only books.

She had noticed it was going brown at the bottom but upon examination I’ve found it’s very brown inside too. Does anyone have any advice, it’s quite a size now and she’ll be upset to lose it.



Many thanks,

 

They are always brown inside its normal, as to the brown patches I'm not sure, but I've seen lots like it.
I dont think it means the tree is dying, but I doubt the brown will ever cover up.