Thanks for the replies everyone.
hir wrote:In a word: immediately.
Treat it as part of a continuous learning process from DSA to AD.
In the good old days we used to have a reactionary old guard who would tell you that you had to wait four or five years... in order to gain sufficient experience to cope with the AD test.
This advice was nonsense - tell your brother to do the AD test immediately, before he has a chance to have his first accident!
This was my first thought, perhaps give him time to get used to the basic principles of driving a car before moving onto more complex ideas and techniques, which was why I asked.
I should point out that my brother is actually older than me (27), but due to circumstances never had the opportunity to learn when he was 17.
What I meant by proper observer was someone who is a qualfied observer to IAM standards (I'm not....yet, although Swatchways keeps telling me I should
) and me being his younger brother may not necessarily pay attention to what I'm teaching him. Also someone who has time dedicated to teaching.
Being the only AD qualfied driver in the family, I've got a lot of respect from everyone on all matters driving so that's why I will be proposing this to him after he passes DSA.
Knowing what I know now having becoming an AD, I want to pass this onto as many people as I can and have them learn the same things, especially someone in my own family.