No, the CIO method really does more harm than good, in my opinion.
Honestly, yeah it is normal if that's the way she has done things with him, and really there's nothing wrong with it other than it can be inconvenient (but aren't babies inconvenient sometimes?). Its called co-sleeping, and its actually like the main thing they do in other countries. America tends to be very anti co-sleeping though, so everybody has kind of a negative vision of it. Honestly its been proven to prevent SIDS and its great for providing a baby with comfort. Here's some info on it for you, so you can learn the benefits of it.
The Benefits of Co-Sleeping
It talks a little about breastfeeding, but that doesn't have to be involved, its just a plus if the mom happens to be also breastfeeding.
And also, always keep in mind that babies aren't babies for long, and in a year or so you can explain to him all about sleeping in a big boy bed. As of now, he's still really too young to understand and he'll probably just be confused and cry and miss the warmth and closeness of his family when he's trying to sleep.
My son co-slept with us up until just a few months ago. Honestly, I never made him do anything, he actually just started asking to sleep in his own bed one day shortly before he turned 3. I think he just got sick of trying to get comfortable between us lol. Now I feel kind of lonely without him!! haha but basically, either way I would wait just maybe one more year before trying to tackle the issue. Its not that long when you think about it, just be patient.
That's my opinion anyway, I know other people think differently.