You asked "Do Ghosts Prove the Existence of a God?"
I find that question to be an interesting topic.
In the West, we 'know' what Ghost look like, but in the East, especially in predominate Buddhist countries, we might have a hard time being able to relate to their ghost. Their ghost typically have their entrails hanging out and 'dragging'.
Why I bring up Buddhists, is that Buddhist in the West typically do not believe in God. Ghost can appear to people who do not believe in God. That is the first answer.
The second answer is 'ghost' can be 'created' thru hypnosis. If somebody can 'create' a ghost thru hypnosis, then that takes the 'steam' out of a God creating the ghost.
Happiness is the result of an enlightened mind
whereas suffering is caused by a distorted mind.