Having to fly while dealing with a serious medical problem or after having specialty surgery at a hospital that's far from your home can be difficult enough without having to deal with stressed security checkpoint staff. If you are moving slowly or are having trouble speaking, the problem is even worse because you can't easily explain to the staff what's going on. While having a family member with you can help, even then there can be problems, as the case of a cancer patient beaten by the TSA in 2016 showed. The solution is to have experienced medical flight assistants with you who can better help you deal with anything that security throws your way.
Better Communication at Checkpoints
Medical flight staff can alert airlines and airport security offices ahead of time to let them know a person with special needs will be coming through. The staff are familiar with all of the regulations required at airport security checkpoints and can help you prepare as your turn through the line approaches. That will also help speed up your trip through security and get you to the gate faster -- something that can be a comforting milestone during your travel because it means you're past another hurdle.
Assistance During Airport Evacuations
Even if your journey through the security line goes well, you can have issues later on. If someone else jumps the security line or if a suspicious device is found, the airport might be evacuated. The medical flight staff can assist you as you head back outside and then later go through security again.
Location of Alternate Forms of Transportation
Sometimes the evacuation or other security problems would mean not being able to take the flight you had to take. Having medical flight staff with you will make dealing with that a whole lot easier because they can help you reschedule the flight or even find non-air transportation, such as a train or private driver. They can communicate to airport staff how urgent it is that you get a flight as quickly as possible; your family might not be able to convince the ticket agents of that.
While you or your family might be able to do this yourselves, it can be a lot harder because you likely don't have the support network and experience that medical flight staff do. If you really want to make your travel easier, contact a medical flight company like Angel-Flights and ask them about their specific procedures for dealing with security problems.