OK Jack is whose twin??

I'm stuck in a dilemma. Many people have recently told me Jack is my twin however I still think he looks a lot like my dad and NOW I think he may look even more like my dad's brother, my Uncle Joel or even my cousin, Grace. I definitely think he could pass for Grace's brother/Joel's son.



And last but not least...Uncle Joel trying unsuccessfully to imitate Jack's famous backwards/forwards wave.