Doors – A hinge door stopper that won’t break easily

Rot needs moisture to get started, so it's unlikely that an interior door frame would be rotten without you seeing other signs of water damage on the walls, floors, ceiling etc. nearby.

A quick test for rot in wood is to try to push the point of a pick or the blade of a small flat-head screwdriver or into the wood: if it resists, the wood is sound and if it pushes in easily, it's rotten.

If you're really concerned that the frame is rotten, you should think about replacing it: it would be very hard to be sure that you've covered the entire rotten piece with hardener just by going through the screw holes.

Otherwise, I'd just go with my advice from the question you linked to.

Some suggestions:

• Regardless of the door type, a good coat of primer and exterior paint will be the better of the finishing options.

• a fiberglass or steel surface should outlast a wood one (they should both be 'trimmable' with the right saw blade)

• Check to see if your door slab could benefit or be harmed with the inclusion of a storm doors. Some doors benefit (water protection) other's can be damaged by it (over heating in the sun).

• consider ripping out the entire door and door jamb and installing a whole new all-in-one pre-hung exterior door. This will allow you to re-square up the opening and also likely give you the most water-tight seal.