Cold, Fever, Nasal Congestion, Breathlessness, Cough. Can I Give Half Deriphylline Tab?

my son is 3 yrs and 4 months old.he developed cold and fever 3 days back,now he has severe nasal congestion , breathlessness,and mild cough .i started with grilinctus bm,sinarest plus and augmentin .hez not improving,especially,his nasal congestion doesnt respond evn to local xylometazoline.this tym i have givn him aal the three medicines ie,oral bronchodialator with mucolytic,sinarest plus,and augmentin.but he still has severe breathlessness,hez craving for air........can i giv half tab of deriphylline 77mg(i have givn grilinctus bm just one and a half hr bak.please advise dr tabassum mbbs