Sister in law's fiancee?

My wife and I have been together for 10 yrs (I'm 30). Hence I have known my sister-in-law for roughly the same amount of time and we are very close. She has been with this guy for about two years now and they recently got engaged much to her dismay as she tells it. My wife and I moved to the same town as them recently and we have been spending more time together. I used to like the guy but now realize he is lazy and really doesn't care about her. For example, he goes to work at 10 gets off at 4 and then lays on the couch until he goes to bed day in and day out he does nothing around the house and does even less for her which is where my problem arises. A month ago we were supposed to go empty some storage sheds that my late father in law had owned it was about a two hour drive and consisted of moving some refrigerators, ac units etc. Instead of coming to help I was sent with my wife and her sister alone to do this while he sat on the couch and got a little fatter. Tomorrow I have to drive my sister in law 45 min away sit for two hours waiting while she takes care of some of her legal matters which are 6 months past due because someone, who will remain anonymous, will not take her because "they don't have time". She can go m-f from 8-5 no appointment necessary. The plot thickens...I had to go by their house today to drop off our power washer so they could use it. I went over my lunch break and this dude is sleeping still. I cannot describe how heated I was! The worst part is that every time I say something about it to her she defends him to no end. I'm at my breaking point and find myself wanting to kick his *** although I know that will not solve anything. But I'm having to pick up his slack since this is my wife's sister and spending time, taking off work etc to do it. I need help before this comes to a head. Thanks!