Who is going to know the key to your safe then? Just use a multi-signature address and give it to a few of your kins and it is harder for any of them to steal and easier for them to find.
Depends how close you are to your family. I'd probably trust my immediate family - but I don't know my extended family that well so I wouldn't put it past them to collude and steal and just claim ignorance.
Best solutions are cold storage (if you plan on using them sometime in the relative short term i.e 6 months) or just multi-signature if you don't need them anytime soon (i.e. couple of years all the way to your lifetime). If you have a soft copy that should always be encrypted and if your having a paper wallet in a non-guaranteed safe location then BIP38 is pretty necessary IMO.