My dad ...

My dad is a big, strong guy. 6'1" 190 pounds. He's a farmer - he's physically active on the job and also works out in a gym.
But tonight I saw him and all I could think was that he looked weak and old.
He is in the hospital. He has a blood clot in his lungs.
My dad is a big, strong guy. He mostly thinks doctors are for sissies, and he never misses work. Tuesday he was sick and did not go to work. Wednesday he asked my mom to take him to the ER. They went. he was sent home. Thursday he went to his doctor. They said to rest and sent him home. This morning he again asked to be taken to the hospital.
My dad is a big, strong guy. He rarely complains. Pain isn't in his vocabulary. His work depends on him to keep going, even if he's sore. Tonight, despite having pain medication pumped into his system, he said it hurt. He said he was in pain. He asked if it was time for the next shot because it hurt that much.
I am not big. I am not that strong. I am terrified of what might happen. Of what could have happened. The ER sent him home once! His doctor sent him home once! What would have happened had they not caught the clot today? What will happen with his recovery? And how in the world did he even get a clot? He has not had surgery, he is not inactive, he did not just take a long flight, he is not pregnant, did not give birth, does not have cancer, didn't have a stroke or a heart attack, none of the things most websites list as causes fit him. So where did it come from? What caused it? What will his life look like in 2 weeks? 2 months? 2 years?
Right now I am just praying that he starts to feel better soon. I am praying they don't discover he has cancer that we didn't know about that caused the clot, or other disorders/diseases/etc.
Mostly I'm just praying he feels better and is home soon and is out of pain.