What Would You Do?

Send him another email telling him if he does not pick it up withing x amount of time, it will be going to a storage facility and he can pay to get it out/or not.
If it does end up going into a facility, just send him the address, phone number and wish him good luck.

Even libraries have internet access.

It would suck, but you can't be expected to store it for him indefinatly, and especially without hearing back from him.