Surfing Waves

My brother likes surfing and now he is going to surfing training under an unauthorized man.He doesn't have any authorization.Is this create any problem.Coach will correctly know the postures we need to keep while surfing .If this man doesn't know then it will be danger .Can anyone reply that is it okay to learn surfing under a person who is good in surfing but not an authorized coach .Feel free to share your opinion.

Where is the " authorization " coming from ? From the government ? From the insurance companies ? From the Life Guards ?
You said your brother loves surfing, so he already knows how to surf. He just needs coaching to refine his skills right ?
There's some surf instructors that don't surf very well, but are good at getting newbies to stand up. There's pro surfers who rip on waves, but don't have the skills ( or patience ) to teach.

The time honoured and most common way of learning to surf is to go with friends and learn from each other.
Coaches are a new thing in the surfing universe.
If your brother has good swimming skills and a load of common sense then having somebody coach him qualified or not could help.
Having a buddy to surf with is a good safety factor.
Where in the world is your brother learning

It's hard to say as there are many unqualified surf coach out there. Especially ones that they hire for the summer times. There are of course certified coach out there who can barely surf.