My Husband, 68, Fell On Our Farm A Few Days

My husband, 68, fell on our farm a few days ago landing on his right upper leg (where his keys are in his pocket). He can hardly put weight on it at all. Tender to touch just where keys would be in his pocket and there is a pretty good hematoma there. No visible bruise. My husband had mitral valve replacement February 2015 and has been on Warfarin since that time. I'm concerned about him not being able to bear weight on that right leg. He's been limping severely for 2 days.