Sure, that would work. And would be the way to go depending how much rot. Minwax Wood Hardener is good to use to make sure any fungus present is dead.
But the Minwax product is very low viscosity and on my boat soaked into the rot thoroughly, and hardened. This gave a surface to apply the two part Marine Tex which will never rot.
This patch has been there for 8 years in Florida with no deterioration. Plus the screws are more secure than with wood.
