After he developed a number of highly successful buildings, Guy Francon was established enough in his reputation that he no longer had to do much actual design work on his own. Peter Keating privately admitted to Katie - his then-girlfriend - that he saw Francon as an "old fraud." Even so, the book said that there was at least some method to his madness, and that he was apparently really good at finding clients. Peter Keating apparently lacked the same ability, and the between an economic downturn and Keating's overall ineptitude the firm went seriously downhill after Francon's retirement.
There isn't a lot of evidence of him dropping in on the firm to give advice or help, though (at least that I recall); is there any evidence of how he felt about the decline in the firm?