Your brother-in-law sounds like a really nice guy - and I imagine he's not charging you a fortune to host your site.

Only you (or your brother-in-law) can answer my next question, which may seem a little "blunt"...

Are you confident that the server on which your site currently resides is configured sufficiently to allow you to manage your site properly, and that the configuration is entirely compatible with the version of zencart you are using?

Remmeber - server software and program software are always being advanced and upgraded, and it is vital that your web host (even if it is your brother-in-law) ensures that this compatibility is 100% retained.

When you are running a simple website (a few html pages displaying pictures of your last family vacation) you can host it on an old steam-driven system.

With e-commerce (when you are taking people's data and credit card info) it's a different story...

Here, the server must not only be 100% compatible with the software, but be extremely secure as well.