Are my sentences correct

I want to thank everyone for praying for my father. He is getting better little by little. Also, thank you to those who went to visit my father at (I would write in) the hospital. I am so blessed to have this group that I can ask for prayer anytime. Thanks!

When do we use "at" the hospital.?

Thank you Blue Jay.
I noticed that not a lot of teachers have been responding to our questions here. Where are they now? I don't see CalifJim, Mistermicawber and other teachers.

I would use in for someone who has been admitted as a patient, and at for someone who is visiting.
All of us come and go—we're not on a schedule. Both CJ and MM have been around today. At the moment I seem to be the only "teacher" here, but CJ might look in again, and MM is in Japan so it's early afternoon for him. The Europeans may well show up before too long, as

I used "at" refering to "visit my father." But you said it was incorrect, and then you explained it to me when to use "at" I'm confuse now. :-(

I should have been more clear in my original post. Sorry. I didn't mean at was wrong, I meant I would use in instead. We usually would say
She is at the hospital (not admitted as a patient).
He is in the hospital (admitted as a patient).
Now, you can say
1. She visited my father at the hospital (because that's wh

Got it! Thank you again BlueJay for your explanation.