but when was he tested?
There are many instances when the test came back negative but they really had the virus
Starting with Patient 0.
The viral load may not be enough to trigger the test...or the test could be faulty, etc.
Bottom line is the fact that he tested negative is not a true reading of whether he had it unless perhaps tested within a day or two of death...and even then there are examples of faulty tests
His family should self quarantine and assume he had it.
That sounds like pretty sound information and advise.