The tree looks healthy to me. It looks like it was stressed from the summer heat and drought. Some of my Japanese Maples look like this by August. The color change is normal for some Japanese Maples. I'd recommend pruning off the dead branches.

Good! Thanks. We had a very wet summer, one of the wettest on record. I didn't have to water anything all summer! But it is in full sun. I was thinking of planting a tree nearby that could provide some dappled sun.

Thanks again.