Each of the other characters either try to help Charlie to enjoy the last minutes of the life he's determined to end or weed out the truth behind why he attempted suicide in the first place. All New People reveals in video flashbacks, nuanced verbal references, and an emotionally charged, climatic confession session prompted by Myron that everyone in the house carries their own baggage, yet here they continue on. What makes Charlie's tragic past so special that he can choose to end the suffering? The play ends after everyone has admitted to their personal demons and Charlie, the very soul the others tried to save, tells a bawling Emma, and by extension Myron and Kim, that everything is going to be okay.
Whether Charlie believes that or is just trying to console Emma isn't relevant. To me, his declaration is a statement about the human condition, that complete closure to life's happenings, good or bad, isn't possible. The character's pasts find ways to haunt them, regardless of the miles traveled, funds extorted, or drugs indulged in -- remember Myron's delivery? -- to escape them. However, people can come to terms and overcome the hurdles, emerging as "all new people" along the way.