I am sending in bahlf of my niece who lives in Alabama in the USA

She is 19 and studying in some college in Alabama.

She is not working and she has Green Card.

her parents are in so good financial situation and wonders if she is entitled to any kind of benefits from the government?

I sincerely doubt it, and certainly not if she had not earned enough to have filed a tax return for 2018, filed in spring 2019; 2018 tax returns were used to determine eligibility for the current "stimulus" payments.

Unemployment pay in the US is typically on an "account" basis - you can only claim pay for x weeks having previously been employed and had payroll deductions into the (state level) unemployment scheme. After X weeks you lose eligibility, and only regain it by working and paying in. So if you use up all your eligibility, then take a job, but lose it after only 3 months, you will probably find that this time you are only eligible for unemployment pay for perhaps x/4 weeks, or less.

She should talk to the college’s guidance counselor to see if she qualifies for any kind of grant aid.

More information required, including what type of institution the "some college in Alabama" is.

Have her stop by the college's financial aid office.

Green Card holders can apply for FAFSA.

She should find out from her parents if they used her as a dependent on their tax return.

It's now too late to file FAFSA for next academic year. Deadline was back in March.
Usually the colleges use the FAFSA information to allocate funds to the students even if they come from fairly well off families - they can match the kids with other funds that are not income related ( subject/background/sport/interests).
Go to the college financial aid office and ask.

It doesn't seem likely based on the limited information posted. Alabama is not exactly the most open in the US when it comes to helping it's citizens. It didn't expand Medicaid under the Affordable Care Act, for example.

I agree she should start by going to her financial aid office.

And if she wasn't a dependent, she could claim the $1200 stimulus payment. Filing a 2018 or 2019 tax return isn't a requirement for receiving it, but it will take time and/or effort to receive it. If her parents did claim her as a dependent, they should get a $500 stimulus payment for her.

The $500 dependent payment is only for minors age 16 and younger.

Well that sucks for those who are paying college bills...

Actually its raised to 24 for those still in full time education.

Link?

You are correct and TKoH is wrong: Per savingtoinvest.com:

Not true. If the student is over 17, even if claimed on the parents' income return as a dependent, the parent will not get the $500 stimulus for the student.

See who will NOT get the checks below:

https://www.pjstar.com/zz/news/20200...ll-be-left-out

Fully agree with Pulaski. This is not true.