that is never a good idea to begin with:
1) brake fluid if hydroscopic meaning that it will attract moisture.
2)lack of lubricity
3)not thick enough to resist washout.
use synthetic brake caliper sliding pin lube designed for brake caliper sliding pins and bushings only. They are meant to be used that way. PBBlaster and the likes will swell any rubber bushings causing them to break/crumble and moisture and dirt will get in.
I personally have been using sylglide for decades with full confidence and excellent results.Vehicles been serviced by yours-truely using sylglide on various brake related rubber bushings, caliper sliding pins, etc. have gone past million miles mark (I have over 200+ vehicles maintenance service records that I performed on) and none of them experienced any brake caliper seizure or damaged rubber caliper boots.
Lastly: if your rubber bushings/boots looked swollen and out of shape, replace them with a rebuild pack (Carlson or Beck Arney) for it may have come into contact with other petroleum products already and will fail fairly soon.
"Internet discussion boards act as echo chambers for conspiracy dittoheads" A.Allen