I just wanted to point out that there are safety issues with every kind of sleeping arrangement. Co-sleeping is the norm in most of the world. SIDS is actually one of the reasons TO co-sleep. Research has shown that moms who co-sleep are more tuned into babe's breathing and will wake if the breathing pattern changes. I have been co-sleeping with one and/or two since my oldest daughter was born 4.5 years ago. Blankets, bumpers, stuffies and other things in cribs are dangerous too. Suffocation is not a risk inherent to co-sleeping; there are other risk factors such as parents who drink or take medication or who may be obese. It is these risk factors that could present in suffocation. As for injuries, it is common sense not to put a rolling baby in a bed without a guardrail or not to put a baby between a wall and a parent.
Peds should not be "scolding" anyone. You are their employer, and while it is fine to share advice or opinions if asked, it is not fine to scold, implying that the parent is doing something wrong. If co-sleeping is wrong, then so is much of the world.
As for your friend, I agree. It is much easier to night nurse and co-sleep. I am still night nursing my 2 year old, and I would be a complete zombie if I had to get up to nurse her several times/night. There is such an emphasis on making babies independant, and I find that sad. They grow up too fast as it is.
I think it is very rare that you find a 10 year old co-sleeper. I would venture to say that there is something else going on in that child's life that needs attention. But, if it works for that family, it is not up to anyone to judge.