I told him about decentralised exchange solutions like Nxt.
I know some people like Nxt or not but it has a working decentralised asset exchange that does exactly what Cryptostocks does except that it is completely decentralised : No attack, no stealing, no service interruption.
Right now, you can only do transactions in NXT coin but soon coloured coin will be added so any currency can be used (even USD, EUR, Doge,...).
There could be an attack any time that could steal everything and make the exchange goes bankrupt. This is the problem of all centralised exchange.
Peershares could also be considered: http://peershares.net/general-information/
It has not yet been released, but the ETA is relatively soon and the platform would fulfill all our needs.
I have doubts about NXT, because of how centralised it is; it does not seem much better than Cryptostocks. Coloured coins would be a necessity for me to consider this option.