Dick doesn't survive; I guess that's part of the thesis. You have a psychiatrist who lets down the people he's treating- it becomes a vicious circle of mental incapacity, and yet you can't look at Dick in the same way as you look at the others. Nicole is genuinely sick; she knows she sick, and because of her illness she seems to be in more in tune to Dick's behavior than he does.
His attempts to genuinely help his patients are derailed by his lack of self control; he parties, he's a womanizer, and he's a liar. Unfortunately, he's really bad at all three and becomes twisted in his own web of deceit. By the time Dick gets to Rome he's completely derailed from the tracks. He is the 'black death,' he is as crazy as Nicole.............. and he's as suicidal as she ever was. It's a very sad story, but the survival of the fittest would negate your thesis if your applying it to his character. You have to apply this premise to a character that actually 'survives.'