“Its not what you look like that matters but its what you are inside” how does the author bring out the truth of this statement through the play 'On The Face Of It'?

by describing both the character who were totally different from each other he has given us an example that how to be strong mentally and dear to accept what the truth was.
mr.lamb a x-solder who had lost one of his part of leg but no fear how the society treat or react on him,a man full of positive thought only.who also teach us how to enjoy,how to smile in ever condition and accept the truth.
but now introducing darry an opposite character from mr. lamb.he is negative thinking,have a lots of fear to accept the truth ,his condition.
from both of their challenges auther want to teach us what the statement is.