Hello, I was invited to a function next weekend. On the invitation it said the dress code for men requires a jacket. My question for teenage boys would slacks and dress shirt be acceptable?

Depends on the event, but it's best if he has a jacket with him

No boys should wear a jacket or blazer...no jeans or tee shirt or flip flops

No

No jeans. That's all I can remember.

That depends on what function you're attending. Evening events are generally more formal imo