I don't want to put a blanket of denial over my head and blindly come to the aid of Tommy, but the guy was a part of Scott's solo band for years As we know, some of those years, Scott was in a pretty dark place (brother's death, divorce, etc).
Maybe his marriage to Jamie and the making of Blaster had moments of "good place" and new beginnings.
Maybe he was starting to heal from losing Jeremy...and getting over the ugly STP split.
The band was hitting its stride, sound-wise, with Joey & Nick...new music was supposedly on the horizon...with Chester leaving STP, perhaps Scott had hopes of reconciling with the band.
I don't know...maybe that's what he means by he was doing better.
Drug addict, enabler or not, I think you still feel pretty awful when you lose two band-mates in less than a year.