A will made in sound mind should be a legally binding document that no one, blood relative or otherwise, can challenge.
The Sun
In reality, without a will any property or money will go to the nearest blood relative.
The Sun
He talks about them so often that everyone assumes he's a blood relative.
Globe and Mail
The guarantor must be over 25 years old and a blood relative.
Times, Sunday Times
I was never a blood relative.
Times, Sunday Times