Like with his other novels, Tóibín is a master at creating real-life characters, people of flesh and blood, whose position you can understand, and even if you can't understand them, they are still presented as entirely plausible and natural. All the characters have own personality and even way of dialoguing: cynical, confrontational, conflict-avoiding ... but at a much deeper level they are thrown together by life itself. They have no other choice but to deal with the situation, and because of Declan's disease, they have to overcome their own all too human smallness to create something grander for the young man's last months.
Even if it's not his best novel - I think his writing style has much improved - its still above average by any standard. Tóibín is the master of the deep emotions of daily life and he loves all his characters. There is no evil to be spotted, unless in fate itself.