whatwas old mr darcy's plan for wickham?

no detail

He was to provide for him.....

Yes -- the late Mr. Darcy bequeathed me the next presentation of the best living in his gift. He was my godfather, and excessively attached to me. I cannot do justice to his kindness. He meant to provide for me amply, and thought he had done it; but when the living fell, it was given elsewhere.''

Source(s)

Pride and Prejudice