What is the Meaning of the Expression
one’s FLESH AND BLOOD?
part of your family; a near relative
This is often used to emphasize that someone is related to you by birth, and that your connection to that person is, or ought to be strong.
Replace one’s with a possessive adjective that fits your meaning (e.g., my, your, his, her, our, their)
His brother, his own flesh and blood, didn’t even come to his funeral.