Who said anything about uprooting his family?
It was a short-term loan to Bordeaux, not Brisbane. If he had football at the forefront of his mind, then it woud have made sense. It's one thing competing for places at a club like United, it's not the same at a club like Bordeaux. Koscielny had been dropped, and they brought in Marcelo from Lyon. Did he really not fancy himself being able to compete with those types of players?
Mourinho lived in his hovel at the Lowry whilst he was with us, his family was in London. It's something managers and players do all the time. Is it that much of a sacrifice in an attempt to get your career back on track to live in France for a few months?
He chose the easier option. Keep picking up his wages safe in the knowledge he was never under any consideration to play.