I don't want to to powerlevel, but a relative I had was akin to Barb personality wise.
Such people can be tyranical and very hard to oppose. They may threaten suicide or harm to the child and I can understand why Bob would back down. Standing up to Barb is not as easy for a family member than it is for a random stranger.
He was at best a mediocre parent. Could he have made Chris into a semi-functional tard who doesn't chimp out every week if Barb was not in the picture? Maybe.
Also, I think his previous family cut all contact because of Snorlax too.