@berrygerry gave you good advice hit up http://www.jwfacts.com if you haven't already.
Tell your dad you've been thinking about returning to Jehovah. You just have a few questions and if he would be so kind as to answer them you'd be willing to study.
He will be so excited by you stating that he'll for sure try to answer your questions.
Here are some ideas for questions.
1. Were those that were disfellowshipped for taking blood fractions prior to the governing body allowing blood fractions automatically reinstated once the governing body changed their minds? and how did they go about apologizing to those that were disfellowshipped after causing them so much unnecessary pain?
2. In 1919 when Jesus chose the organization we taught that he should be worshiped. How can that be? Either they were teaching darkness then and he wouldn't have chosen them or we're teaching darkness now because we're not following the teaching we taught when he chose us? "In Jehovah there is no darkness at all"
3. In the book the "Time is At Hand" we stated on page 101 that Jesus took reign in 1878 and that Armageddon was in 1914. Then we said 1925. These were specific years/dates. Doesn't that directly contradict Matthew 24:36? And again why would Jesus chose us if we were teaching such things?
4. If there was a governing body in Jerusalem why were the Pharisees part of that body given the condemnation Jesus game them? See Acts 15:5
5. If I'm out in service how do I explain to the householder the concept of overlapping generations directly from the bible considering that the bible indicates in Matthew 1 that a generation is roughly 48 years?
and there are many many more tough questions like this that will scramble his brain if that is what you're looking to do. What I mean is make him think.
This is not chicanery or twisting words these are things flat out said by the organization over the years. If he wants you to "return" he should explain the above type questions which he won't be able to because it's all a farce.