I often see retaining walls. If I had to guess a percentage I would say that about half have some movement. In this case, it's a darn good thing there is a retaining tree!
This tree has been on the job a long time!
I see fences all the time that are held up by vines and plants.
I see sheds all the time that are held up by vines and plants.
But I have seldom, if ever, seen a retaining wall held up by a tree!
And this wall frames a working driveway and garden!
This tree is important!
Another couple of years and maybe another one will be needed. Maybe two or three!
They should think ahead!
Let's see, what kind of tree would be best?
Should this wall be repaired? Doing so might actually harm this tree! And then it would have no reason to live.
My recommendation: sometimes things look bad, but really might not be! In this case, though, a couple of more 40 year-old trees might be advisable!
Actually you can see that the wall is crumbling around the tree. How much longer will the wall last? I am being tongue in cheek about it being held up well and that only a couple of trees are needed. When this collapses it will be a mess, and the driveway will not be usable. It's probably best to get a real wall there now! I don't know who has responsibility for the wall, but when replaced, obviously, it will need a good guardrail!