As Opus 17 indicated, the Roth IRA that you inherit from your dad will never be your own, it will always be your dad's Roth IRA maintained for you as beneficiary. This inherited Roth IRA must be maintained entirely separately from your own IRAs.
An inherited IRA can only be moved by non-reportable trustee-to-trustee transfer. It is not permitted to be moved by distribution and rollover. Any money paid to you from this inherited Roth IRA can never be rolled over (although the resulting cash can be used to pay for whatever you wish, including using the money to subsidize a new contribution to your own Roth IRA that you are eligible to make.
