Re: Oh, God. I might have to cook Thanksgiving.
Invite them to come around early on the bullshit premise of a shared communal cooking experience for family bonding, if your Dad usually does all the cooking and the rest of ye are as bad as you say then chances are he'll end up taking over and doing it anyway. If youre feeling especially lazy make sure to show him what an absolute mess you're making of your dish so he cracks and insists on doing it himself.
Even if he doesnt and it turns out bad you can blame them and if it turns out good you can steal all the kudos.