Hi.
Under wallet info, there is also the possibility to print out his private key to make a backup as I think absolutely safe.
I'm still a bit old school
This thing actually you need to do while you are creating your account on the MEW site. This the kind of backup you can do but actually accessing the wallet with the private key may lead to loose the fund since web have more change to go with incorrect website and hacking attacks.
@Jacee
You may decrypt the MEW wallet with the .JSON file, Private key, Mnemonic phrase and Metamask. Can use anything this list and decrypt your wallet.