Technically, you can mutate the wrapped component (since it is just a JavaScript object/function), but you should never do it. In React, HOCs should be pure functions without side effects.
If you modify the prototype or properties of the wrapped component inside your HOC, you are permanently changing that component for the rest of your application.
Don’t Mutate the Original Component. Use Composition. Resist the temptation to modify a component’s prototype inside a HOC. Mutating HOCs is a leaky abstraction —the consumer must know how they are implemented to avoid conflicts with other HOCs. Instead of mutation, HOCs should use composition, by wrapping the input component in a container component:
HOCs add features to a component. It’s expected that the component returned from a HOC has a similar interface to the wrapped component.
HOCs should pass through props that are unrelated to its specific concern