Poor Tom, it seems there are unspoken/unmentioned assumptions that trip you up every time. At least Ron is out of the way and can't cause further problems though I suspect Albus' picture and Severus will not appreciate this (methinks they'll appreciate even less the assistance Harry & Hermione have brought back). It's going to be rather amusing watching the remaining purebloods trying to understand and maintain the gizmos when they understand nothing of the theory and knowledge behind them (I'll wager that even the appropriate manuals, assuming there are any and, given wizard logic, that's a questionable assumption, are either missing or not understandable by under- or mis-educated purebloods). It looks like Tom's in for a most interesting time.
I'm sure the manuals either left with the 'blood traitors' or are under conjured tablelegs to even them out.