YES, absolutely! This is exactly how the website is set up to assist you "aid your inmate".
https://www.inmateaid.com/ask-the-inmate/if-my-inmate-did-not-appear-on-your-search-for-an-inmate-but-i-know-the-jail-he-is-in-will-he-receive-the-letter-s-after-i-set-him-up-with-a-profile#answer
Accepted Answer Date Created: July 27,2017