yes they are allowed check the tsa website before talking
TSA: Travelers with Disabilities and Medical Conditions
Disability-related items permitted through the security checkpoint include:
Wheelchairs
Scooters
Crutches
Canes
Walkers
Prosthetic devices
Casts
Support braces
Support appliances
Service animals
Baby apnea monitors
Orthopedic shoes
Exterior medical devices
Assistive/adaptive equipment
Augmentation devices
Ostomy supplies
CPAP machines & respirators
Hearing aids
Cochlear implants
Tools for wheelchair disassembly/reassembly
Personal supplemental oxygen
CO2 personal oxygen concentrators
Tools for prosthetic devices
Medications and associated supplies
Braille note takers
Slate and stylus
All diabetes related medication, equipment, and supplies
Any other disability-related equipment and associated supplies