How can I save Van Helsing from Renfield?

Hint 1 of 3:

Did you hear about a way to protect yourself from "loonies"?

Hint 2 of 3:

If you went to the asylum on day 1, the guard should have given you something
to help you out here.

Hint 3 of 3:

(You will need to go back and visit it earlier on that day if you met Dr.
Seward the first time you entered the asylum.)