I know the world is full of rotten folks, and I know that they die and have funerals.
And I don't think one should blatantly lie about the person's vices. If your uncle had kids all over who didn't even know him, I don't think he should be eulogized as "a dedicated and loving father."
I just can't imagine that a funeral would be turned into a smear-fest by the preacher, of all people. We can avoid touchy issues and find something nice to say that will console the mourners and give some sense of meaning to the life of the deceased.
I do not believe that the minister at my uncles funeral was able to fool the Good Lord. Surely he fooled no one in the handful of people that were in attendance.