"I believe that the taxpayer is entitled to all the credits but was looking for another opinion to either dispute or verify."

Geez; you asked multiple questions:

"Can he claim the EIC"

"& Child tax credit?"

"Also can he file as HOH? "

No one except you knows their conditions and qualifications for each thing, so you would work through each ITA.

"Why do I even bother with this forum."

If you already worked through all three, is there something specific that makes you doubt what you got for results? Because you didn't tell us anything about that part. You simply ask three parts as if we can work through each one for someone we know nothing about.

Sure, people without kids are getting EIC.

Sure, people are getting EIC, and even using 2019 income for that purpose.

And no offense, but, it's hard to tell who the issue of HOH applies to, because there is no perspective in how it was asked. Both the client and the fiance might be "he" nowadays. I'd rather make no assumptions while trying to work through questions for which I have no information.