Haven't nurturing this idea of trading a Bitcoin in the near future,but one question that's always come as a concern to me is. Is proper for me to trust a friend of that high magnitude ?
Not for that matter. Everything related to money doesn't make me dare to give them confidence in doing it.
Selling or buying something that is processed by ourselves is different when it is processed by someone else even though that person has 99.99% trust.
How about one who actually have zero or no knowledge about the crypto but have an interest on investing so as to enable Him grow more weather?
This can be done through a learning process. The current learning process about buying and selling Bitcoin is quite easy and there are lots of videos to watch. Buy in small quantities first, when you can, then buy the desired amount.