Free Hosting Terms Of Service
"Personal accounts are to be used by the primary owner only. Personal account holders are not permitted to resell, store or give away web-hosting services of their website to other parties. Web hosting services are defined as allowing a separate, third party to host content on the owner's web site. Exceptions to this include ad banners, classified ads, and personal ads. x10Hosting reserves the right to refuse service and/or access to its servers to anyone. Each individual is allowed ONE account only."
Also, you are fully responsible for the content and security of your own account and website(s). If you grant access to a third party and that third party violates the terms of service your account could be suspended and terminated.
Disc space is not "unlimited". It is unmetered. There are no preset limits on disc space so long as you are in compliance with the terms of service.