Incorporating this way of eating into my entire family’s routine.

I have a husband who is ready and willing to participate with me to address our health and eating….but my 9 year old little boy who is a rail is addicted to sugar. I know his addiction to sugar is soooo bad but I don’t want to completely mess him up psychologically. I would love to completely remove all flour and sugar from our home and go cold turkey but my kid is so tiny that I’m worried he’ll lose even more weight — so I cave in and I let him eat crap. He will barely touch a vegetable much less chew it and eat it. Help. How do I create a healthier environment for my little guy, spare him from developing the horrible habits we’ve developed and still help him find a space to feel “normal” and empowered?