They do not look structural, so they should just be a straight ahead job of prying them off the walls, and then reattaching new ones.

Make sure you can get new ones before you rip the old ones down though!

If you cannot get new ones, those can be repaired believe it or not. A lot of people do not know this, but Bondo adheres to wood just as much as steel on a car, so it can be mixed up and used to form the rot back into shape that is impervious to water. Kind of messy to work with, and a pain while working at height, but it hardens quick, and then can be rough sanded, then finish sanded back into shape. Just mentioning it as an option.

I had a stained glass window where the bottom portion was getting kind of punky, and bondo saved the day. Just easier to mess with bondo then replace the window sash.

Whether you replace in its entirety (they certainly seem to be holding up the overhang) or piece together, fabricate a flashing to cover the tops and lap down a little. Copper or aluminum could be used. Attach with correct nails to the sides. Once painted you won't see it.

I was going to suggest Bondo too.

Sorry but Bondo is literally the worst thing to use on wood. It is much harder than wood and expands and contracts less, which leads to fine cracks developing between the wood and the bondo which lets water in which leads to much more rot, now hidden. The proper mateial to use is a product called wood epox by abatron (west system makes a similar product but the abatron product is easier to learn) Wood epox was designed to mimic the density of wood perfectly. A liquid is used first to harden the damaged wood then a putty form is used to patch. That said the damage on these brackets looks pretty extensive so you will want to replace as much with wood as possible.

First picture is way past repairing with Bondo/ Abatron.