Hi My Father In Law Has Developed Severe Swelling In

Hi my father in law has developed severe swelling in his feet, and subsequently in his legs, which has resulted in him been unable to stand, he was diagnosed as having GOUT, I cannot agree with this .
He is an 80. year old and has always led a very active life. He has now got to the stage where he cannot even stand, what do you think we can do to help him?