Ask a doctor or an expert to answer me and an object. My grandma and his grandma are half sisters. And her parents are close relatives, aunt and uncle!

Counting blood comes from two aspects:

First of all, your relationship with her

The first generation: your grandmother's father (also her grandmother's father)

The second generation: your grandmother and her grandmother.

The third generation: your mother and her father.

The fourth generation: you and her

You have just passed three generations and can get married.

Then talk about her parents' uncles and aunts:

Aunt, you didn't make it clear whether her grandma and grandpa are brother and sister. I guess her grandmother and her grandfather are brother and sister.

If so, it will have little impact on your descendants. As long as your grandmother's father's ancestors have no obvious genetic diseases, children are no different from ordinary couples.

If this aunt is her grandmother and grandfather, I suggest that you don't get married or do more tests.