The child cannot swallow his own secretions, and cannot breathe on his own because of that.
If they do a trach, he will be able to breathe on his own, just like his sister did for 6 months, without a vent. The parents will probably need suction to keep the trach clear, but they will not need a vent.
Please, read the medical report you posted, read the facts about his sister's case, and stop making assertions that are not supported by the evidence at hand.