My dad was baptised Baptist, has drifted away for awhile, and is now interested in converting. I am an active Catholic. Can I act as a confirmation sponsor for my dad??
While it is possible (canon law has no prohibition of it) it is not recommended. A sponsor takes on the role of a kind of spiritual adviser/guide/example for the one to be confirmed. It would be a bit awkward for familial roles to be reversed in the spiritual realm. I would recommend that your father choose another person to be his sponsor for confirmation. If it is highly impractical for him to do so then you could discuss the situation with your parish priest and he can discern with you whether you as the sponsor would be appropriate.