Brat,
No one is immune. Like you said, Life was good he may have felt so good that he had to test himself. "Maybe just one...See, i can do it ...I'll have another".
That's my own fear. The miracle is that he didn't kill anyone or himself.
The al-anon site is linked to these pages. The support you will find here is Amazing !
I will send good thoughts to you and your family.
Cindy