Parents need to know that there's abundant gunplay (rifle fire) as the Colonial militias face the British Redcoats, with some extras falling dead in both direct confrontation and sniper-style fire. The young hero burns his hand in molten silver, a vivid trauma in the book for generations of young readers, handled more discreetly here (the crippled limb isn't even shown in closeup). An ultra-religious character comes across as stern and domineering, but not cruel. The Esther Forbes novel is still required reading in many schools; kids today might be tempted to watch the movie instead of doing the reading.
Positive messages:Early Revolutionary War lessons here include an oratory that this is to be the start of a long, hard campaign, not just a party throwing tea into Boston harbor, and that there are serious issues at stake in the uprising. One character is depicted as a strict Puritan type, whose stubborn religious streak leads to Johnny T's fateful wound. Unlike later Hollywood views of Christians, he's not hateful, and no comparison is made between his conservatism and the views of the rebel Boston patriots.
Positive role models:Johnny is a hardworking, proud youth who only wants to make his own way in the world, but he becomes a spirited fighter in the Revolution and understands the issues (at least the Disney interpretation of them). Females take a supportive but mostly background roles. One strongly religious head-of-household is inflexible in his Bible-based beliefs, but not at all unkind. One young black boy who may or may not be a slave represents the minority presence. It's clarified that the crude "Indian" disguises of the Boston Tea Party aren't suppose to degrade natives but just make the rebels harder to ID. Even some English are sympathetic to the colonists.
Violence:War-conditions shooting, with dead/wounded bodies, but no blood or gore. Johnny famously sears his hand in molten silver, but it's not graphically depicted.