When a man is cornered in a bar fight,and feels his life is at stake, he'll grab the nearest weapon to hand In order to survive. It's a case of act now, and reflect later. united cannot be gratuitously criticised for this.
If Mourinho was truly available, this is a roll of the dice over which they had no meaningful choice. They've had to prostitute everything they claimed to hold dear in an attempt to keep up with us, but they can't be overly chastised for that. They aren't the first organisation in human history to reevaluate their moral compass when placed in a corner
Will it work? Given his track record, this is a possible outcome that can't be discounted, but long term, united seem completly unequipped for the challenge that faces them.
Like the hare in the fable, they've been caught napping and any panicked attempts to throw their diminishing weight around shouldn't detract from the fact that however successful Mourinho is, their period of imperious dominance is over. The only question mark, is to what extent.