Adding adult sibling and her kids as dependents

[Robert944]

My sister and her kids did live with me all year. However, I don't own/rent the home, owned by father, but I do help pay for food, utilities and helped with transportation.

We are all US citizens, both single, in Florida.

She did receive government assistance for her and her kids, snap and medical, child support for one kid, but didn't earn anything outside of that.

I did work year round and supported myself financially.

She has given me the right to claim her and the kids. The father that is paying child support did not live with us last year, and she has full custody.

Our father doesn't want to add them, and the father of her one child didn't add them on his taxes, so I'm the only one to declare them. 

Our father didn't work and only received social security disability, I have the higher gross amount.

I probably need to speak to an expert but unsure if I can get help without having to pay for someone to do my taxes. 

[MarilynG1]

Here's the Qualifications to Claim Someone as your Dependent.

In order to claim someone as your Dependent, you have to provide over half of their support.

If you provided over half of their housing, food, clothing, etc. you may qualify to claim them (and your father too).   Here's more info What does Financially Support Mean?

@Robert944