If I understand you correctly, he wants to leave the fiat on the exchange for some time and buy just at the right time?
I'd calculate how long it would take exactly for your money to appear on the exchange after depositing and just do the deposit when it's almost time to buy the Bitcoin, so the money is basically only a few days on the exchange instead of maybe weeks or months.
It's better to pay a bit too much for those Bitcoins than taking a bigger risk of losing the fiat on the exchange.
I don't care how safe a certain exchange is, bad things can always happen.
well thats the problem... you CANNOT calculate or predict huge dip... thats the problem... look at etherum for example... thats jhust not poissible. You have to have funds on exchnage and the orders already in place (buy XX BTC at 1300 USD price (for example). Your solution would be preferred (i did think of it myself also of course) but its just not possible. You would miss that sweet price.
Also the price might not FALL (for logn periods of time) to 1300 or similiar but just DIP there for some tiems (seconds, minutes, hours... a day)... friend cannot afford to lose this opportunity to buy just because he has to wait for bank to transfer money to the exchnage or to hunt somebody on local bitcoins to sell him for this price... he has to "be in position already"...
So Bitstamp is the safest option. Bitfinex should also be legit and big, altough they have money withdrawal issue (or something). What about BTC-e? I heart that they are "owned by russian mafia for money laundering purposes", nobody really knows who owns them, BUT they so far didnt suprisingly scam anyone... is that true?
What abotu kraken? Should be also quite big legit european exchnage, correct?