The Fackelmann scam and the wraith's return
It occurs to Gately that right now’s just like when he was a toddler and his Mom and her companion were both passed out or worse: no matter how frightened or scared he might become he now again cannot get anybody to come or to hear or even know about it; the discredited tube to prevent vicious or inspired bleeding in his suspicious Trachea has left him completely Alone, worse off than a toddler that could at least bellow and yowl, rattling the bars of its playpen in terror that nobody tall was in any shape to hear him.
Context
Directly after the late-day-dread paragraph: the dread's origin scene recurs as present fact. The tube has made the childhood terror literal — alone in a room, unable even to bellow — and the capital-A "Alone" is the same isolation Kate and Joelle describe from inside depression, arrived at through pure circumstance.