According to ToS:
3.6. The User shall not sell (or buy), rent, exchange or give away an Account.
But as far as I know, your home is not on our surveillance list and our SkyNet drones are not scanning who is playing on your computer (YET!). So if you will be very careful and avoid detection, there is a big chance that we will not ban you for allowing your dad to play on your PC. But be aware that you are responsible for what he is doing (damn, you will need to be a dad for your ow dad!).