Hi there Komsen
I am not an expert, so this is only what i have been told.
I thought that there was another post on here regadring "Pillow's" and babies but i cant find it.
However since you have not been answered i have asked my CHN the Question for you (I hope that is ok?)
She advised me that you shouldn't have anything(including pillow's) in the cot until 18 months, and that a child should not have a pillow in their cot/bed until at least 2yrs of age.
Remember all children are different and so is parenting so if you want a quick response or a second opinion i would give "Sids" a call or talk to your GP as they will be able to put your mind at ease.
But personally i wouldnt put a pillow in your sons cot, i just wouldnt tempt fate.
I hope I have helped you or at least pointed you in the right direction.
eìí? DD Haley 2 yrs old eìí?