Very funny!
I'd hit him if my way was groped in the dark! Parser, you didn't know that groping has sexual connotations?
I don't think you can grope 'a way'. You can grope your way along.
His way was groped in the dark. ("In the dark" modifies "was groped.") Not good
His sister was groped in the dark. Since his sister doesn't have a 'dark', I think 'the dark' refers to 'the darkness' or 'a dark place', 'in the dark' being a locative adverb.
His way in the dark was groped. ("In the dark" modifies "his way.") Not good
In the dark his sister was groped by a drunken English student.
His way was groped by him in the dark. ("In the dark" modifies "him.") Not good.
He groped his way along in the dark.
"He gropes his way (along) in the dark" 'in the dark' an adverb of location, pointed at 'gropes' I think.
Since 'in the dark' can literally mean 'in the darkness' or figuratively 'not know', is it an adverb or an adjective in the following:
I am in the dark on this. Cf I am clueless on this.