Can a 14 year old apply for imunity on their own or do they need an adult's help
?
There is no "immunity" in immigration law. However, if you are referring to the "deferred action" 2 year work permit, then yes, he can apply on his own.
Sorry, one follow up. At 14,he cannot work in the United States anyway (the legal working age is 16), so this might not be the best option for him. If he was to be put in Removal, there are other ways to get the case deferred based on prosecutorial discretion.