I'm sorry, Matt.
You didn't let anyone down, any more than I let my parents/family down by having CP.
They may feel let down....but it's not our fault, or our place to fix that.
We just have to learn to live with it - easier said than done.
I don't have to tell you how much p*****g in the wind the drinking thing was, either.
I'm sorry they got to you so badly, and I'm sorry you let yourself be let. Sometimes excuses sound pretty damn good, I know....but you're right - it's always an empty promise of healing and respite.
This wasn't your screw up to 'fix', Matt - and maybe, if anything good can come of this, you'll take that to heart this time.
hugs
D