I have a question regarding a single gentleman approx 65-70 yr old. How would someone get guardianship for him?

I'd call adult protective services. Since he's over 65, he's protected by law in many ways. APS saved mthr when she made it onto their radar.

Depends on why the landlord is not renewing the lease. There are laws protecting tenants from discrimination.

I wouldn't do either for a stranger. A POA can only be used when a person can no longer think for themselves. Guardianship, a person has to be found incompetent to handle their affairs. The Guardian also has to keep all receipts of how the persons money is spent. The state gets involved. The landlord should,in writing, tell a person their lease will not be removed. What you may want to do is get APS or Office of Aging involved. This man needs to be evaluated and a new place found for him. It's hard enough caring for a LOL let alone a stranger.

If this person is competent and cooperative they could assign you power of attorney to handle their affairs.

ddmack, yes a landlord can refuse to extend a Lease. Thus the tenant would need to move by the end of his current Lease. As for giving notice to the tenant, it would be best to do it in writing, but it all depends on the verbiage in the current Lease.

Below is a link as to how to get guardianship of an elder.
https://www.agingcare.com/articles/how-to-get-guardianship-of-elderly-parents-140693.htm