Complex sentence: An emotional Lucy thanks Tom for rescuing and raising her (being the only father she can remember) for the few years on Janus, and after introducing him to her son/his grandson Christopher, and the two promise to stay in touch.
Split into simpler sentences: An emotional Lucy thanks Tom for rescuing and raising her (being the only father she can remember) for the few years on Janus. She introduces Tom to her son (his grandson), Christopher, and the two promise to stay in touch.