правилен is a short adjective (the full form is "правильный" and it's more commonly used) When it applies to a person it means that his behavior is proper and (politically)correct but not that he is right about something.Originally Posted by TiaraNEug
Some examples with правилен (правильный):
Этот подход к проблеме абсолютно правилен. – This approach to the problem is absolutely correct.
Вот правильный ответ на этот вопрос. – This is the correct answer to this question.