He told his class last year in kindergarten that no one likes him. The teacher handled it well, but it upset her and some of the other children. He has very low self-esteem. He is a very caring boy and would do anything for anyone, but I have noticed that when he does have friends over he pulls away from them or they end up fighting.
I am most worried about him saying he wants to die. I don't know if he is doing this to get my attention or if he was overly tired. What can I do?
A child's concept of death changes as he gets older. Children ages three to six often think that death is reversible and that a dead person will return. At around age six until around age nine most realize that death is final, but some may still think that the dead person could come back. Your son may be viewing death as an escape from his current unhappiness, but one from which he could return when things are better.
I would begin by taking your son to his pediatrician. Doctors today are recognizing depression in younger and younger children. Fortunately, depression is treatable with medication and therapy. You could also ask your pediatrician or your child's school counselor for a referral to a therapist for further help.
You don't mention your son's or your relationship with his older brother. Is he a "super kid" to whom your younger son may be compared by others? How does your younger son view your relationship with his brother? These are topics you may want to discuss with the therapist.