But are you savvy? By reading this thread i suppose not, cause windows is safe as any other system if properly used. This "omg windows is unsafe" thing is false
Not really, no.
More than 90% of all malware is written for windows.
So statistically, 9 out of 10 times you get malware on your linux, it won't do shit. Alone this makes linux/mac more safe to use with crypto than windows.
But even if you ignor this fact, the fact that you have hundreds of services running on windows compared to about 5 or 10 in linux should make it obvious how big the difference in attack surfaces between windows and linux is.
Not to mention that linux is mostly open source and way better inspected than closed source windows with daily vulnerabilities being discovered..
@OP
It mostly depends on the amount he want to store.
Generally, an USB stick with an encrypted version of the wallet file is not the ideal solution since each time you want to access the wallet it has to be decrypted (which opens up attack vectors).
If he is going to store a reasonable amount, tell him to get a hardware wallet.
Or, if he isn't going to touch the coins for quite a long time, let him create a paper wallet (properly offline).
But if the amount is relatively small, a proper (password protected) wallet should be fine.
If he doesn't have the intention to support the network, electrum (
https://electrum.org/#home) should be suitable for him.
He even has the option to use electrum with 2fa (does cost a fee per transaction!). In this case the funds still stay under full control of your friend, but they can not be stolen since the PC does only hold 1 out of 3 keys. Another key is hold by TrustedCoins (the 2fa provider), and the 3rd key can be retrieved from the seed he has to back up.