It makes me so angry to hear that when you go to the school for help they are saying "he is just lazy and doesn't want to do the work". what a cop out! I see that translated as "we (the school) are lazy and we don't want to put forth an effort to help you". Does your son recieve any in class services or one on one time at school? I had to request this in our IEP a few years ago and it really helps difficult child. Especially if he is having a hard time with math or something. I communicate that to the spec. ed lady and when she has him a few days a week for an hour or two, she will help him with that.
I would contact the Special Education director at your school and ask for suggestions from her/him.
Oh, and also, we have had an advocate since difficult child was in kindergarden. Alot of them are free, I was surprised to find that out. They are a huge help with suggestions and ideas and they will make the school accountable.