What is symbolic of Thomas Perez in The Stranger? Why include him in the novel?

Though his
appearance in is confined to just two chapters, the timing of the
appearances of Thomas P©rez are vital to understanding how the society that judges Meursault
perceives him.

Thomas P©rez had been "inseparable" with Madame
Meursault and he takes her death "very hard." In fact, the doctor refuses to allow him
to attend the vigil, presumably because he is overwrought. P©rez's emotional attachment to
Madame Meursault stands in stark contrast to the indifference and even annoyance of Meursault at
the death of his mother and the cultural and societal expectations that he attend her vigil and
funeral and demonstrate his grief for those in attendance. His inability to produce those
emotions attracts attention in a way that will come back to haunt him when he is on trial for
the murder of the Arab.

P©rez is limping and unwell, yet he insists on
following the funeral procession in the extreme heat because of his devotion to Madame
Meursault.

Later, at Meursault's trial,...