I'd check first for a state online charter school. The most common programs are Connections Academy and K12, both of which will be completely online at the middle school level. This route has the advantage that (in addition to being completely taxpayer-funded, and thus much easier on your budget) their curricula will be more closely aligned with your state frameworks, and will also be required to receive IEPs written in your state (with obvious changes for the online format).
CA has some flexibility in pacing and leveling, and uses standard Pearson e-textbooks. K12 claims similar flexibility, and writes their own curricula.
Being comparable to conventional public schools may or may not constitute rigor for your DC, of course, but likely will make it easier to go back and forth, if needed.
For all online schools, be aware that they may fill up enrollment very quickly for next school year, since many parents are considering the same kinds of backup plans.
