Did you bother asking why he is giving away the account for free? This should have been the very first thing you should have asked before even showing interest in the account.

But all the same, since he is not asking for money or anything as a reward, I don't know what other ways he might try to or want to carry out a scam assuming he is a scammer, what I did advice you do is to make sure you change both the email address of the account, as well as it's password, and also check the withdrawal settings to make sure the account is not set to only send bitcoin or any other token to a particular address only, else, you might end up working for the real owner of the account...

While changing credentials, make sure to use a new Ema and new password (password and email address you've never used any where before).
I am not actually sure if freebitco supports the change of account email address, but just check it yourself.