What Happens if Income too low...

I know there was something in the big bill about this but I can't find it...

I have a friend who is expected to have no to very low income next year as she's helping her elderly parents. She has low income now but has been on ACA. She told me that she doesn't want to go on Medicaid so will project some type of income for 2026. She doesn't understand that there's a repayment penalty. I'm just not sure what it is and I'm trying to help her. Is it the full repayment of premium including any subsidy received? Is there a penalty? She's not financially savvy at all and I think she's messed up 2025 too but I'm more concerned about 2026 right now for her.