Teen68,
Thanks for the post. Sorry to read of your father's ordeal.
Diabetes is a risk factor for complications after bypass surgery, so it is possible that the diabetes is contributing to his problems.
The poor kidney function and swelling may indicate heart failure, or may be simply from "stunning" of the kidney, or from another source altogether.
If your father is in a smaller center, consider having him transferred sooner rather than later. As a general rule, large centers do better with complications than do small.
Good luck.