Secure File Hosting Service

I don't know where to ask this question so hopefully I'm in the right forum. I have a friend that owns his own company and travels alot. He needs a place where he can store his work files (mostly document like word, excel, pdf, drawings, etc...) which contains very sensitive information. He need a place where he or the people in his team can transfer files and that he can setup access levels for his users. He need access to his files with a secure tool such as sftp or something else that you guys can recommend.

Also, since some files can be very large he requires a good transfer speed from everywhere in the world. He's looking at around 100GB of storage space and a very high transfer allowance. He will probably need to host his website also. Do you guys think it's better to host the files and website separately?