If the company is legit and trustworthy I would advice your brother to buy their shares,but if it is not I would advice home to go into business but I don't think cafe business is moving well anymore due to easy gadget this days.
The problem is that even the shares of many good companies can also fluctuate when it comes to price. Buying shares can be profitable and I am not saying that investing money in shares is always risky. However, there IS a risk involved.