For what it's worth, my late friend Nick S, a PHD chemist, gave me some DOT 5 fluid in the later 1980's. I used it to fully rebuild the drum brake system in my 64 D100 in about .1988.
The wheel cylinders started failing in about 2021 or so, and I had to replace them.
The fluid owed me nothing, as they say. I use it in everything old school now.
Mark