His enclosure would be much easier to heat if it wasn't so tall- his hides DO belong on the floor of his enclosure- yes, BPs are ground dwellers.
What I said & meant was that his entire enclosure appears to be on the floor (sitting on carpet?) and floors are normally drafty & cooler than if the enclosure is on a cabinet sitting ABOVE floor level. That's not helping you keep his enclosure at the right temperatures, no matter if it's winter or summer. Cool air in your room sinks to the floor year-round, making this already over-sized (& TOO TALL) enclosure that much harder to heat.
And he still has next to no privacy other than his hides. BPs are shy snakes. Easy to see why he's not eating.
What is the actual temperature on HIS floor, inside enclosure?