That's pretty sad if we had our own fans booing him. He has done nothing to merit that, in fact quite the opposite. He has helped pull us it of a hole and provided some much needed entertainment value. While everyone is entitled to their opinion it would be better all round, in this case, if their opinions were formed on the basis of some factual information.
It might also be worthwhile looking in the mirror and asking yourself what you would do in your work situation given a superior financial offer before jumping on someone's back for doing what you might probably do yourself.
Let's suppose he does have an offer and he is considering his options, I would think he is more likely to stay if fans are making it obvious that he is really wanted here. I'm sure the booing will just make it even more likely that he will choose to move on. Why not make some banners and work on making him stay ? Let him know how much we would like him to remain at Motherwell. Show our appreciation, sing his name, applaud him. It's much harder to leave when you realise how much you are appreciated and wanted.
Whatever he does I wish him well.