I'm not a tree person at all, so hopefully someone who is chimes in for you.

But I am a plant guy. And a lot of plants can benefit from a good pruning. They tend to show some more vigor in their growth afterwards.

My suggestion would be to maybe try pruning off those lower branches, up to just above your roof.

Definitely on topic. But we’re a small community so I don’t know if you’ll find what you need. I’ll do my best to help as much as I can.

Have you checked the soil moisture around the tree? Changing drainage patterns can definitely affect tree health. Does the soil seem waterlogged? If so, it could be causing root rot, which would explain the yellowing needles.

Also, it kind of looks like the tree has a large trunk injury, but it’s hard to tell—maybe it’s just grown into an odd shape. I would want to probe into that a bit to to see if there is any decay happening in the trunk—if so that could be the issue.

Unfortunately, neither of these problems would be easy to solve. And in my experience with conifers, they don’t show stress as readily as other trees. Once they start yellowing like this, it may mean that they are very sick and recovery will be a long shot. But I have very little experience with this exact species.

If you really want to preserve the tree you might need to hire a local expert. Get someone with a lot of experience and who is coming from a tree preservation mindset. ISA certified would be a minimum and a consulting arborist would be best. Might cost a bit more but this is a very unique specimen so I think it would be worth it depending on your finances.