Having invested in BTC at 18000 level and loosing 17 BTC is just like a next to suicide case and if I get that much money I will retire momentarily and will become financially free too.
Money is a very very powerful resource in this world and if we calculate then your friend has actually lost 17*18000=306000 usd. oh my God that is 0.3 million usd.
I can understand with what kind of pain your friend is going through, I hope he has not exhausted completely with his saving and I would advise to take a break at least for now and his mind must have been going through a volatile phase as of now. So takig a break is the best solution.