Hi there I'm going through my 4 month olds wardrobe up to the next size ready for winter and in those items are some little track pants and matching Jumpers- I've been told these may be unsafe to dress my little one in? He wouldn't be sleeping in them at night but he does nap in the day and in the car ( he has his own air vent in the car) Are they ok for times like that or should I avoid altogether? They are a cotton polyester blend that big stores like big w etc sell. Kind regards