Well, I am certainly not a bass player but what I've been told by friends or even by BJ Tribute band memmbers os that BJ Bass parts are really not difficult at all and even a medicore bass player could play most of them.
I don't think Jon would have taken him back in 1983 if he were just shit. I am absolutely sure.

The drugs and the alcohol were probably a huge problem but let's remember that Tico was an alcoholic for a whole bunge of years but he is still here.

Perosnally, I can't believe Alec was fired because of his bass playing. There was something else but I don't know what it is.

However, let's think of STEVEN ADLER from GnR. He was fired only after he could really not stand on his feet anymore. This would be reason enaugh but Alec seemed ok to me....well, whatever...

I hope he is happy. I liked that dude a lot!