You cannot change the CFrame of a model as it does not have one. Instead, make a primary part for the model and weld all of the model’s parts to that primary part and set the primary part’s CFrame. That will let you tween the whole model.
I would also like to note that script.Parent.Parent is not a CFrame value. Use script.Parent.Parent.CFrame.
You need to make a part and attach all the other parts to it using welds or weldconstraints depending on the situation for the model. Then you will be able to tween the primary part instead of the model.