When my father felt someone was lazy, he'd say they weren't "work brickle." Has anyone else ever heard this expression, and if so, what is its derivation?

Etymology: Middle English brekyl, brickyll, brukyl fragile, weak,
brittle, probably from Old English -brucol (as in [AE]brucol
sacrilegious, onbrucol rugged, scipbrucol causing shipwreck), from
brecan to break -- more at BREAK
dialect : BRITTLE
©W3

so, work brittle: think Maynard G. Krebs (work!!)

but is this just opposite of your father's usage?

That makes sense, beanie--think of butter brickle! And welcome aBoard!

I just found this site when looking up a term used by a friend of a friend years ago, "brigglin". When asked what he was doing, he would say, "Just brigglin." The one who used it is dead, so there is no way to verify the meaning, as used by him, and my friend thought it might be from the French word "bricoler", which means "to putter", or to not work very hard. Could it have traveled up the Mississippi from French Louisiana to the state of Iowa? My friend is going to ask the deceased friend's wife what his ethnicity was.

this is probly just some sort of coincidence, but there was a style of pottery called Briglin; thus Briglin pottering.

That makes sense