inpatient, in patient

Inpatient or inpatient ( one word ) means someone who is checked into a hospital, to stay there overnight or longer--
Your friend is an inpatient, so he'll be on the second floor.
Will he be an inpatient, or will they treat him and release him today?

In  patient or in patient ( two words ) means in a state or condition of  ( in ) bearing delay, waiting, or misfortune calmly and without complaining--
She waited in patient silence, while the clerk ignored her.
He waited in patient misery, until help arrived.

Now that you know that, you can say--
"He waited in patient good humor while they admitted him as an inpatient."

Note--"in patient" ( two words ) might also mean within a place ( in ) connected to someone undergoing medical treatment ( patient )--
Talk to the nurse in patient services.