Hi,
I agree with the people who say "do go".
Like Steph said, you may get closure from the experience.
In my own life, I've found that I often require resolution to my feelings and for eras that have passed. Whether you liked the person or not, you seem to have unresolved feelings concerning his disapproval of you. In the long run, you obviously have carried on without that man's support and you may find some kind of release in acknowledging this by attending his funeral.
Think of it as a small ritual that will maybe allow you to dispense with some uneasy feelings.
You may also dump any negative feelings you have by using some personal introspection and, if you feel that you can do that, you don't necessarily have to attend the ceremony.
My concern is just that you don't allow yourself to retain any anger or bitterness over the past. This man's death seems to have dredged up some issues. It is not the man, but the issues, that you want to deal with.
Take care of yourself,
Rebecca