My 7 month old has these white yellowish things that cover his eyes and they are sometimes red, what could be the cause and what can I use? He also has a runny/blocked nose, he coughs and sometimes vomits after eating and his appetite has declined

????????????????? Sorry but the description does not make much sense. What part of the eye/eyeball/lids/brows/etc. are you talking about? I'm afraid someone would need to look at these to make any sense of the issue. It may or may not have anything to do with the other symptoms.
See your M.D. The baby's symptoms warrant a visit with the PCP. He may have a bacterial or viral illness. Please monitor his temperature, keep him well hydrated, and see your PCP soon. If he is having difficulty breathing, please see the Emergency Dept. For his nasal symptoms, cough and vomiting, nasal saline rinses will reduce post nasal drip. A cool air mist humidifier may be used to lessen cough.