sick baby

As

my oldest (18 months) caught what I'm assuming is a sinus infection she has no fever but her nose is runny and she has a cough I've been giving her an alternate between hylands cough and cold and zarbees cough syrup with some Tylenol and it seems to be helping well now my 6 week old has it but she's not coughing as bad as my oldest but her nose is congested..what can I do for her? I've been using the nasal aspirator on both of them. I know there isn't a whole lot to do for my youngest cause she's too young but there has to be something lol