I've got a different view from everyone else, I wouldn't worry about it. The tree seems to be deteriorating in a normal manner. The needles and smaller limbs fell off long ago, and now the bigger limbs are falling off. The sap is long gone and much of the weight is out of it. What will probably happen is the rest of the limbs will fall off and drop straight down and then the top will break out, and all of that will just drop straight down and won't bother the blind. At some point what's left of the trunk will break and fall, but that will likely take years.

The tree was a bigger danger to the blind when it was alive than it is now. I have a couple of similar sizes pines in my front yard that died about 5 years ago. Not much left to them, but the trunks are still standing. Woodpeckers love them.

The time to cut the tree was as soon as the needles died. If you cut it now , there will be some danger involved, especially since you have no experience with dead trees. I'd leave it alone and let it fall naturally, one piece at a time.