Oh, yikes! Sorry about the tornado & glad you're still in "one piece". I'm not personally up on BTS- if they're like snakes, when it's too cool they tend to go off eating & start thinking about brumating, & some snakes are difficult to convince to resume eating when it warms up again. No idea if that applies to a BTS though.
But what I can tell you is that it's very hard to keep his regular tank warm enough- in an emergency (like an ice storm, which I have done!) it's much easier to keep reptiles in minimal space (like an ice chest or thick styro-foam box- the kind they ship frozen food in) with something to keep them warm. It's all about insulation- you might instead insulate his tank & only allow minimal air flow. (heat rises up & out easily)
IF you have a hot water heater that runs on gas or propane, you can heat reptiles very well with jars or water bottles filled with hot water. You'll need to refill them when they cool off, obviously, but in an insulated chest, they take about 8-10 hours to cool off. If you keep him in his tank, it depends on how well you insulate it as to how warm he'll be- but even if only one area is kept warm, that he has access to, that should suffice- he'll have the option. At least Sunday isn't too far off, & you can probably allow more of a nighttime temperature drop?
Again, I'm not up on keeping BTS, & I don't know what temps you normally keep him at, but our member dakski is, & he should be around sometime soon- hopefully he'll offer some advice too. https://ball-pythons.net/forums/member.php?49533-dakski