How to play the same server of Minecraft on 2 diff PC?

*sry for lengthy explanation**
So I use Windows 8, and play Minecraft paid version on PC. My brother and I both have to share the account because my parents don't want to pay for my brother's account. (I got my account from a gift code from another friend). There are some instances where my brother and I play minecraft at the same time on the same account (but different singleplayer servers of course).
Does this affect anything? Recently my dad blocked the official Minecraft website (minecraft.net) so I can't play it on MY favorite servers/singleplayer. Now I'm using another computer to play Minecraft. However, I can't see my personal servers I created in Singleplayer. Is there any way to fix this? Do I use a flash drive? Twitch account?
(I've only played PC for about one week but I'm not totally a new beginner either)

Generally, single-player games do not occur on a server, and are called "Worlds" by most Minecraft documentation.

To transfer your single player worlds over, you need a flash drive or upload site. The flash drive will be easier to do.

Go to the old PC and look for your Minecraft folder. There will be a folder marked "saves" and in that folder there will be more folders, one for each single-player world that still exists on that PC.

Copy those files onto your flashdrive, and then copy them from the flashdrive into the same Minecraft folder on your new computer.