Thanks everyone. I gave him a larger water bowl and put cold water bottles wrapped in towels in his tank that im changing a few times a day. Also turned the heat off completely. Ive also gotten my apartments overall temperature down, which has helped a lot. His tank is still quite warm but it seems to be cooling down a bit (fell from 83 degrees to 75 during the night but was up at 78 this morning). He really liked the water bottles and burrows around them. He also took a soak in his bowl and he isn't as stressed as before.
The forecast said the heatwave should last the next week and then we get really stormy and rainy weather. Hoping he wont be too stressed from this.