My DS 7months has a viral throat infection and also has a blocked nose. This is causing him to have trouble settling down to sleep as well as feeding. So I've put a pillow underneath him and he settled immediately. Obviously I can't leave it there all night so my question is would it be a problem if I put the pillow under the sheets so that it provides him with some comfort and props him up to breathe easily? He tends to roll a lot in his sleep and often moves on to his front.