There's no reason that an 85-year-old grandmother from Minnesota in a wheelchair should face a pat-down and the same security precautions as a 23-year-old Syrian national.
Actually, there is.
Is a grandmother going to be radicalized? Unlikely.
But think of this: Someone with malicious intent finds out that granny is going to fly. They tell her that "look, you don't have long left to live anyway, Smuggle something aboard this aircraft and nothing will happen to your grandchildren".
Everyone could be coerced into this. Doesn't even have to smuggle it onto your own aircraft, just past the checkpoint and hand it off to someone else who will use it on another aircraft. Granny gets to see her grandchildren again, some other plane with complete strangers has an accident.
Everyone should have the exact same scrutiny at the airport, healthy or ill, young or old. Because if we create a loophole it can be exploited.