Falaises struck me as a deeply pessimistic novel and it would be a mistake to see Olivier's Adam's world view as not bleak, although there is light at the end of the novel. Bearing in mind his later novel Les Lisières and what I wrote about it, it's interesting to note that the word lisières (edges, frontiers, borders, etc) is mentioned several times in the novel. These could very easily apply to the edges of the self.
The family is an important element in Adam's writing: the family can of course be wonderful, be a healing influence, but also be sheer hell. Adam said of Le Cœur régulier, 'Rien n'est vrai, mais rien n'est inventé': 'Nothing is true, but nothing is invented'. People fall and try to get up again, and after the narrator's mother in Falaises – a short time after being released from a psychiatric hospital – throws herself from a cliff, the impact is profound.
Siblings different and similar, family problems, leaving home, despair, drug taking and severe abuse of alcohol to escape the hell of reality, casual sex, suicide, violence, all present here and all usual in Olivier Adam novels.
My other posts on Olivier Adam:
Olivier Adam: Je vais bien, ne t'en fais pas
Olivier Adam: Des vents contraires
Olivier Adam: Le Cœur régulier
Olivier Adam: Les Lisières