Prayers for the Procedure

So here is the latest from Jen & Mom at the hospital:
Dad's vital signs are better BUT he's not out of the woods yet.
He slept comfortably last night.
He's off the blood pressure support because his blood pressure was stable
The kidney numbers look better.
The white blood cell count was down- this is a good thing

Here's the bottom line:
He's having a procedure at 11am to "FIX the PLUMBING."
This will take between 1 & 2 hours.
The obstruction in his kidney needs to be fixed.
The procedure will drain his kidney.
But this is much like renovating a house, they will go into the organ and there could always be surprises and risks.
So dad is still in critical condition and needs prayers that this procedure at 11 is successful.