A notarized letter of authorization is required if a person other than the owner applies for registration.

When you apply to take it there is a section that asks your experience.  

@Estefania Concha Unfortunately your tenant is correct in the fact that you must have a "tenant at fault just cause" currently due to the tenant protection programs...normally this does not apply to single family residences owned by an individual. 

However, I’d like to know if he can still apply for any government aid for first time owner in a multi family property.

The same applies to development, flips, etc.

Most of these you register your house and send requests to the tenants to apply.

So I would be mindful of that (again, depending on where you live), because there are trolls out there who apply for jobs or housing while intentionally hoping they don't get it so they can sue.  

My architect and I sent them over assembly bill No 811 on ADUs and mentioned that the looks to be in violation of the bill quoting the following:"Accessory dwelling units shall not be considered by a local agency, special district, or water corporation to bea new residential use for purposes of calculating connection fees or capacity charges for utilities, including waterand sewer service, unless the accessory dwelling unit was constructed with a new single-family dwelling"They responded saying that this didn't apply to the ADU and quoted the following"(B) For an accessory dwelling unit that is not described in subparagraph (A) of paragraph (1) of subdivision (e), alocal agency, special district, or water corporation may require a new or separate utility connection directlybetween the accessory dwelling unit and the utility.

The phrase “don’t put all your eggs in one basket” applies directly to this concept, as spreading your investment across a broad spectrum is how investors balance risk and reward in their investment portfolio. 

We have a running list of researchable things that will also probably apply to your situation too.