i bet you are like no he's not but listen.
i have been watching the kh3 trailors and sora and ven look alot alike.
i do think that ven looks like he is too younge to be a father,but on kh 1 when sora was looking out the window and a storm was comin so he left and he's mom walked in his room and said"sora dinners ready."
she sounded younge like 19 or 20 so you never know.
its sqaure enix for you they couldve had a hidden affair and ven left or something and never talked or seen eachother again.you know you have only heard his mom talk and never his dad so that could be right.