There's a possibility your dealing with a respiratory disease, possibly mycoplasma gallisepticum. If in fact he has worms, they couldve weakened him to the point of compromising his immune system allowing a disease to take ahold. If this is the case, it might be best to have a necropsy performed if and when he dies. Keep him seperated from your other birds and remember biosecurity. Consider getting him started on tylan 50 injectable, 1/4cc injected into the breast muscle once a day for 3 days.