Q: Does the whole steering column need to be replaced in order to replace a fried steering column module?

I would ask the mechanic for the exact part number of the electronic component that he believes has failed. Or, at least have him "name" the part and indicate where in the column assembly the part resides. The steering column is made up of many parts, most of which are separately serviceable. As discussed below, limp mode (reduced power) has many, many causes. Consequently I would also ask the mechanic to explain to you EXACTLY how he arrived at his diagnosis and ALSO have him show you the exact test results, on a diagnostic tool, multi-meter, or scope, that has led him to conclude that the particular "module" has to be replaced. With no evidence and no intelligible confirmation you would be taking a risk.

YourMechanic does offer a reduced power (limp mode) diagnostic. If you request a reduced engine power diagnostic the responding certified mechanic will give you confirmation of the cause of the issue in your case. Typically, a vehicle’s powertrain control module (PCM) will have stored one or more diagnostic trouble codes that will identify the "general area" in which the fault lies in the engine management controls. Although the throttle control system is a common trouble area with reduced power, there are quite a few other components and systems that could come into play and, of course, there is always the possibility of multiple, or "coincident", faults. Here are some of the possibilities that YourMechanic dispatched technicians would consider:

Defective throttle position (TP) sensor
Defective oxygen sensor
Defective accelerator pedal position (APP) sensor
Loose or damaged wiring
Defective throttle body
Defective powertrain control module (PCM) (not typical; ONLY if a long, long list of other possibilities is ruled out)
Any fault/error that will affect drivability function
Any fault/error that will affect vehicle performance
A fault/error in the emissions system
A fault/error in the throttle control system
A fault/error in the transmission control system

If you request the recommended diagnostic the mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.