Thing is, they'll probably do alright. Belgium have such a good team that something truly catastrophic would have to happen for them to miss a major tournament, or even get through the WC group stages.
So whilst he's a shite manager and appears a poor appointment, I reckon this could go a long way to rehabilitating his reputation. And to be fair away from the day to day of club football, it also gives a still young, once promising manager a lot of time to learn and improve.
This really is a fantastic opportunity for him, the best he could've hoped for, and he could come out the other side of it a much better manager.