The objective of this quest is to free Kadlak's spirit from the wolf form. It mainly is played at Ysgramor's Tomb which is north-west-west of Winterhold:
You will almost exclusively run into companions spirits at Ysgramor's Tomb. They do tend to have a lot of health, but also aren't very powerful. Most of the times I found myself bashing their shield in instead of actually fighting. I found that tanking in this quest is very successful as you only run into a few enemies at a time which makes this quest very easy to complete.
Defeating Kodlak's Wolf Spirit:
I remember that Kodlak's Wolf Spirit can be hard to defeat. Poisions do not work on spirits. Also I am pretty sure you can't use enchantments against it. Because it is a single enemy you can tank the damage easily. Do watch your health because often times you loose health much quicker than you expect. Once you are low on health lead Kodlak's Wolf Spirit around the basin so that it can't attack you and use magic to heal. Potions are an expensive but quicker alternative.