I tend to think of him as "the old man" because there are so many other well-known Bachs - his sons.
He apparently dedicated all his music to the glory of God. I think he must have been a happy Christian, because even in the St. Matthew Passion, there are no melancholy passages; perhaps he was incapable of it!
Listen to this piece sung by the wonderful Thomas Quasthoff, Mache dich, mein Herze, rein. A most lovely, lilting melody. Beautiful!
Make thyself, my heart, now pure,
I myself would Jesus bury.
For he shall henceforth in me
More and more
Find in sweet repose his dwelling.
World, depart, let Jesus in!
Happy Birthday, old man! I'm sure he is very happy where he is.