I have found the last stage of Proving Honor to be extremely difficult when I first encountered it. There seems to be an endless stream of Draugr Deathlords as well as weaker Draugrs. At some point, you and Farkas are fighting 6 Deathlords at same time and they all have disarm and unrelenting force shouts. Those Deathlords seem to have infinite health and whatever you do don't seem to make a dent on their health. How do you overcome that overwhelming odds?
There are several things that work to your advantage:
1. Farkas cannot die.
2. When Farkas is not disabled, he can do really good damage against these Draugrs.
3. These Dragr Deathlords do not regenerate, but you and Farkas do.
So, one very basic way of getting through this area is to simply run around and not get hit too often. You just need to stay alive. Eventually Farkas will kill of all of them if you survive long enough. It may take a long time but it will be done. Maybe it will take 30 minutes, maybe an hour. It may seem strange how can you dodge 4 Draugr Deathlords and 2 Draugr Scourges chasing after you? But it can be done. They are quite slow. Keep running round the circles near the altar area. Run away to the balcony and go back and forth. If you get surrounded, you can jump on the table, or jump off the balcony. Or use your whirlwind or unrelenting force. Or find an opening and and sprint out of there.
If you want to end this fight quicker, you can contribute by damaging them. Just make sure that you don't get hit too many times and watch your health. Go back to running away if your health gets too low. These Draugrs are vulnerable to fire. And you just learned Fire Breath dragon shout on the wall. If you have a dragon soul, you can use it to end the fight quicker. It does pretty good damage. You can also use the flame spell, even if you are not normally a magic user. Just be patient and don't panic. These draugrs have a lot of health, and it will take long time to kill them.
Depending on your play style and level of your character, you may not have found this level to be challenging. For example, once you reach level 30, disarm will go away.
[Edit] I have since discovered that it is not normal to encounter a room full of Draugr Deathlords at level 10. It was due to a glitch. The problem went away after running verify game cache. I did not encounter Deathlords at Dustman's Cairn until the character was above Level 30 after the fix.