We may not be perfect

My son since grade 3 has not shown any interest in school. I noticed wen walking to school that is a 15min walk I would have to leave 1/2 early coz he would walk very slowly or stop for 5min to do nothing but sit there. I would talk to him to hurry and get to school just as the bell goes. Now in high school that is the same distance or closer he is missing first 2 classes every morning that’s everyday coz if his unwillingness to keep up. He has done my head in numerous times and nothing I do or say helps. He is messy so I keep his room clean as we rent and I dnt want us to get kicked out, he’s never missed a meal my husband makes sure there is food even if he has to work all day and cook it himself he always make sure my children and I are fed to getting up early and make their lunch that they dnt eat till they get home.. We talk with him all our kids to instil values as we dnt hav much as it is. My daughter (younger) is now showing signs as he is.. we have a baby that I am up with to having to deal with his behaviour I’m tired.. What can I do?