Can a Retired (Social Security Benefits) jobless person be a joint sponsor? I-864a

[MotherAndDaughter 0]

I am the petitioner, my mom is the beneficiary, and my uncle would be the joint sponsor (I-864).

His current income is his Social Security Benefits, which is not enough to meet the poverty guidelines, but he will use his house, money in the bank and car as assets to reach it, as well as my grandfather's income who will be the household member (I-864A)

My uncle had enough income, he had a really good job for the last few years, but this year he lost his job. He's been receiving the Social Security Benefits for a few years, so is it okay to use it as income? Also, while filling out form I-864, it requests for the "company" he's retired from, but he's not retired from a company so that's why I'm making this question, and I don't know what to write in that field.

Thank you in advance