Would my Mum be eligible for EUSS?

Hi,

I am of Indian origin with Irish citizenship and living in the UK since 2009. My widowed Mum has an Indian passport and a US Green Card. She's with my brother currently but due to a change in family circumstances, I would like to apply for an EUSS for her. I have thoroughly scoured through the .GOV website but the information is convoluted and I am very confused.

I would greatly appreciate it if someone could tell me whether she is eligible to apply to the EUSS. She's got health issues and is dependent on my brother & me for care but is financially secure.

Many thanks
GG