If Aristotle truly believed in a Supreme being, he had no idea who that being was.
That is a curious statement, especially because it sounds most like Socrates. Socrates had no idea who that being was, but sought to find that being because he thought his life depended on it. He blames his contemporaries for thinking they are sufficient without it.
As for Aristotle, we can dispense with my assessment or Schaeffer's or anyone else's and take it from the philosopher himself:
If then God is always in that good state in which we sometimes are, this compels our wonder; and if in a better this compels it yet more. And God is in a better state. And life also belongs to God; for the actuality of thought is life, and God is that actuality; and god's self-dependent actuality is life most good and eternal. We say therefore that God is a living being, eternal, most good, so that life and duration continuous and eternal belongs to God; for this is God. --MetaphysicsAnd having given the attributes, the next question he asks is how many there are:
It is clear, then, why these things are as they are. But we must not ignore the question whether we have to suppose one such substance ore more than one, and if the latter, how many.True, he was a pagan, but that can also be a good thing.
I think Schaeffer is the best Christian philosopher of the 20th century, save Lewis. He was right on about the marriage of Aristotle and Aquinas. Aristotlean ideas led to Galileo's persecution as the RC church had an Aristotlean view of the cosmos. That's what they get for adopting a pagan's philosophy.
I read philosophy mainly to understand the thinking of the enemies of God, and certainly not to form my philosophy. My philosophy comes from the Bible. The ONLY philosophers I like are christian philosophers.