Hmmm...maybe mature trees do just fine in Seattle, growing up out of grass after having their roots chopped off, not here in Wisconsin.
Looking at the site, that tree is doing better than I would expect. I have seen thousands of trees that look like this one, not 'cus they were topped by unskilled treemen, but they slowly die back from the tips, and then are deadwooded by skilled arborists.
When a mature tree has it's roots damaged, it often takes 5 to 8 years for the damage to show, maybe longer. As the tree slowly dies back, it may take more years before the homeowner notices the dieback, and more years before they do something about it.
Looking at this tree I would take into consideration about 10 to 20 years a possible time frame for the original root damage.
This time lag is what makes diagnosing tree problems so difficult.
Perhaps it wasn't construction damage at all. Look at the grass, even that's all brown. If grass can't grow there how can a forest grown tree survive there?
In any event, they should spend their money on carefully removing the stress's on this tree. I would do a soil test, and see if I could sell carefully installing some compost and mulch to replace the grass. while you dig for the soil samples, you have a chance to see how bad the compaction is. Once the results of the soil test come back, sell them on soil compaction and fertility corrections, if any are needed.
Removing any living branches from this tree would be harmfull to the tree, IMHO.