Dads are funny animals.
There seems to be something in their brain function that compels them to want to fix stuff. Replace light bulbs, tighten the screws in a wobbly chair, replace the washer in the faucet that is drip-drip-dripping, etc.
To his way of thinking, the only "correct" way of life is the JW way of life. Anything that does not fall within the scope of the JW way of life, needs to be fixed. As a parent, he probably feels that it is his responsibility to see to it that your life gets "fixed" to his satisfaction. It's part of his hard wiring.
Having said that, he needs to come to the realization that your life is yours, not his, and he is no longer entitled to try to "fix" it. That's your job, and (when you get down to the nitty gritty) none of his business. Does he still answer to his father? Should an adult be required to answer to their parents? In a healthy relationship, that shouldn't happen. There has to come a time when "a man will leave his father and his mother and will stick to his wife and the two will become one flesh" - the adult child leaves the influence of his parents and becomes responsible for his own family. By the time that happens, your dad's job of parenting you should have been completed, and you will have the responsibility for your choices as an adult - it is no longer his job or his role to continue to "parent" you when you are an adult.