What is a summary of four different characters from four different stories with the same themes in the book You Are Not a Stranger Here?

You Are Not a Stranger Here by Adam Haslett is a collection of nine short stories which all deal with the themes of depression, loneliness, and mental illness. The alienation and loneliness are portrayed as more intense and emotionally complex when focusing on the gay characters present in the book.
In "Notes to My Biographer," we follow a lonely and aging inventor who is trying to reconnect with one of his three children, the only one who wishes to see him. From his initial presentation, we are inclined to think of him as one of those tough old men who can take on anything, and yet we learn later on that he is suffering from mental illness, is bankrupt, and refuses to take his medication. His manic tendencies, left uncontrolled due to lack of medication, have completely isolated him. He has also neglected his children, and Graham is the only one who will see him. Graham is also isolated; he has inherited his father's manic tendencies and is forced to take medication in order to lead a normal life.
In "Devotion," we encounter an aging brother and sister, Owen and Hillary, who live together. Their mother committed suicide when they were younger, and they cannot stand the possibility of being alone, as it would feel like being orphaned a second time. Although they have each thought about leaving the other for a man they both fell in love with, they still need each other's protection.
In "The Beginnings of Grief," we find another story of isolation and loneliness. The unnamed protagonist is an orphaned teenage boy. His mother committed suicide, and his father died in a tragic car accident. In order to deal with his grief over the loss of his parents, he finds himself unconsciously attracting violence. He is sexually attracted to his classmate Gramm, a homophobic jock, who violently beats him and introduces him to a world where pain and pleasure are synonyms.
In "The Good Doctor," we meet a compassionate psychiatrist who feels less lonely and isolated when he immerses himself vicariously in his patients' sorrows. This allows him to distance himself from his own life, which is a barren landscape. He has never been able to maintain a functioning relationship for longer than six months and has become, in fact, his own martyr. He suffers for others not out of compassion and sacrifice but out of his parasitic need to leech onto others' sorrows.