Yes, TB was the big imponderable.
It was totally unpredictable.
It would take some family members but not others.
My mother's aunt and young cousin died of it in the 1930's but the lady's husband and other daughter were unaffected, as were my grandma who nursed them both up to their deaths.
Given that they were next door neighbours and the kids were constantly in and out of both small houses, it's amazing that no one else fell victim to the TB.
No wonder that it was a secret, much-feared ailment.
My gran lived to 93, all her children were long-lived, except one daughter who died of a heart attack age 59. No other early heart disease in the family.