the dipsomania that runs two generations on schedule — "probably not helped at all by…"
probably not helped at all by the man’s very gradual spiral into the crippling dipsomania of his late father.
Context
The family disease is named as inheritance before the novel shows anyone drink, and named twice in the same breath as a spiral that arrives on schedule: the grandfather a dipsomaniacal tragedian crippled at his nadir, and the son, decades on, doing the same "very gradual spiral into the crippling dipsomania of his late father." The word chosen for both men is identical, which is the point — the thing is heritable and it is patient.