When you get your digital thermometer/hygrometer, report back what it reads that his temps are on the cool and warm side. I'd recommend buying some velcro, so that you can mount the thermometer at ground level on the cool side, and run the probe to sit inside the warm hide.

You want to measure ground temps, not 1/2 way up the enclosure (many keepers stick those dials on all the way at the top, or 1/2 way down and aren't measuring ground level temps).

Only offer food once a week. Don't handle him right now - watch his behavior - when he looks like he's lurking from his hide watching for food, then try offering a live mouse IN his enclosure.

If all else fails, you may want to consider moving him to a tub set-up. My very first ball python was housed in a 20 gallon tall then a 20 gallon long. I was determined to make it work. In the end, he fasted for 8 months. I moved him to a more appropriately sized tub and he ate the following week, and the week after that, and the week after that.

Tanks work in some cases, and in other cases, can be very difficult to achieve ideal temps AND humidity. If you use a lamp at all, you're probably misting several times a day to keep the humidity up.

Good luck!