The rules for Medicare as far as I know are you have to have 40 quarters or 10 years of work, if you don’t then your spouse should. Or you will have to pay a higher premium to buy Medicare.
For recent immigrants, younger plate usually covered under their employer plans
Older immigrants who are not working have to wait 5 years before they can buy Medicare coverage.
Medicaid is need based, but immigrant and/or their sponsors have to show in immigration application that they will not be a public burden and a sponsor has to be a certain percentage above poverty line to sponsor. Some states have handled the 5 year stipulation differently from what I have read.
So the question is if you can’t claim poverty then what are the options?
Here is a link.
Health coverage for immigrants
Get information on rules and options for immigrants at Healthcare.gov.