After his journey to stop both the Enclave and another enemy group, and after finding out about the death of one of his friends and their family, he decided to come back to Vault 107 along with his friend and new colleagues. Of course, he gained weight during his journey, but that’s okay.

They gave respect to the family of his friends and Dieter decided to relax and enjoy the rest of his life in the vault.

Unless something happens next, but that’s not important for now.