Some people do actually piss themselves when they die.
I can't tell if that's piss on his pants or not. It does look like it.
Going by the pattern, the stain on the pants looks like it happened while he was leaning forward on something.
The man is lying on his back. Blood pools within a torso much more readily than it spurts out towards the ceiling.
I've seen stabbing victims die from hypovolaemia with very little apparent blood loss, until you start to see Grey Turner/Cullen's sign.
Another consideration is the age of this gentleman. At 90 years old, he's relatively dehydrated (comparative to an anatomical male), which means less blood loss required before death. To have continual dramatic blood loss, it's the required that the victim be alive. No cardiac activity means no steady flow.
There is nothing overtly suspicious about this picture, in my opinion.
Unlike your murder fantasies, people irl don't just lie down while they're being stabbed to death. 91 yo or not, the guy was still a war veteran. He probably put up a struggle and staggered around while he was dying.
It looks like the attack started with both men standing near the foot of the bed. Then Will Sr buckled over onto the bed, face down, bleeding. Then rolled (or was shoved) on to the floor. Look at his hand. It's still up at his face in a protective position.
"Some people do actually piss themselves when they die."
Well, yeah, that's why there's kudos to keeping to the legitimacy of it all if it is an act. 
If I was pretending to be a corpse, I wouldn't imagine that sort of thing being easy.
As is it looks more likely than not. The time stamps crossing with the news articles I can't find any flaws within.
Well, someone told me in chat that the man got stabbed 5 or 6 times, but looking at the picture, there is no way that's true. There's just not enough blood.
The body does look like it was moved to me, but I can't see the whole room, so who knows.
I'm very suspicious of the picture. It looks staged.
Body was moved. Didn't stay long enough on the bed for the blood to stain through. Probably died laying on his chest (explaining the size of the piss stain). Doesn't seem to have a lot of blood on his shirt, didn't bleed out.
I think it's pointless to wax lyrical about a pixelated crime scene, Reap.
I would entertain the possibility that the stain on his pants is blood, rather than urine, and that he was in a seated position on the bed before he died.
But I'll reiterate the pointlessness of this exercise, because there's a lot of evidence we can't see. I don't imagine this is a particularly complicated crime scene.