A very good question and this is a situation I dealt with.

My mother married to my father thirty plus years, divorce. About ten years later she is diagnosed with cancer, I went to every available source...same answer.

1 If my father was retired she is entitled to the same benefits.
2 If my father was deceased she is entitled to his benefits
3 I applied on her behalf, but, she could not receive both Medicare and Medicaid....Medicare pays by percentage while Medicaid paids 100%

Hope this helps some