Henry is 'looking for a friend' and this is no fault of his own.
He represents the 'cushion' that civilization offers its citizens. Human beings need restrictions, and if human beings are devoid of those restrictions they will revert to an 'uncivilized' state of being. It is Roger who actually creates the irony. Henry does not ask to be the one in the 'spotlight' regarding the internal conflict of 'civilized man' nor the possibilities present when 'civilized man' is taken away from those restrictions. Henry has the armour of civilization on his side but it does not defend him. Ironically this leaves Henry isolated, separated and alone.
In Chapter 4, Henry becomes absorbed in playing with small creatures in a tidal pool. Roger begins to throw rocks at him. Henry notices the stones and. at first he's concerned. Then, thinking it a joke, he looks for the "friend" who has thrown the stones. The irony is that it is Roger who is throwing the stones, missing on purpose, not because he doesn’t desire to hurt the boy, but because “Roger’s arm was conditioned by a civilization that knew nothing of him and was in ruins.” It is obvious Roger is no "friend" of Henry; he's just too afraid to hit him on purpose because of societal conditioning.