depends on where u are storing your btc, if its on a pc - wallet , it will be safe as long as u reconnect ur pc,
I think you meant "safe as long as u don't reconnect ur pc". It can be safe even if he connects internet as long as he knows how to secure his computer from malware.
otherwise I Suggest u use an online wallet to store your cash and email encrypt it for extra protection! now days can even get mobile verification
Storing Bitcoins on an online wallet is worse than storing it in a local wallet.