Carl cared about the quality of the music. I find it hard to believe that he would have supported removing the second best singer in the band.
Al himself has said that, due to Al disagreeing with Mike's business moves with the band and Carl not backing Al, there was some estrangement between Al and Carl.
Unless someone is willing to come forth with *some* morsel of new info about what Carl was thinking back around that time, the evidence at hand suggests Carl had by 1996/97, even prior to his illness, given up on aspiring to anything new or great with the Beach Boys. The live shows were certainly professional and Al and Carl sounded great vocally, but the setlist had been pretty stale for years. It seemed even for Carl to be a bit of a job, a business. So while I certainly would hope Carl would have tried to fight for Al, I don't think it's impossible that, having already rolled over and let Mike take control of the touring band, that Carl would have continued on even with Al booted.