Given the task definition and input, reply with output. In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.

Sentence1: 2 year old Jon was at his foster parents' home when he got a call. Sentence2: His caseworker had found him a new mom. Sentence3: He went to a playground to meet her. Sentence4: Over the next few months, he spent time with his new mom. Sentence5: He cried when she was finally able to adopt him.
Foster parents, His new mom, Jon, Jon's caseworker