whooping cough and choking child

Hi,
4 weeks ago my 7 year old had a strong allergic reaction to something in the wood. He had a violent sneeze attack for about 5-10 mins. The very next day he started to cough. Nothing big, nothing worrying at that time. Looked like a v. mild cold. After a week his cough grew more and more persistent and more productive.
His cough wasn't chesty, chest being clear and at that point there were no obvious symptoms it could be whooping cough, but from about week 4 his night cough has changed.
Now at week 5 we're really struggling at night time.He coughs at day time too, but not as violent and there is no chocking or suffocating. His face turns red as he coughs and coughs for a few seconds, but recovers quite quickly and is his normal self.
Night time coughs are coming in fits (3-5 times a night),they always start just before midnight and my boy get scared as he coughs and gasps for air, there is also a lot of stringing saliva coming out from his mouth that he constantly tries to swallow and chokes on... and belches really loud a few times. Last night one of those cough attacks went on and on, for what seemed a couple of minutes, not giving my child much space to calm down and recover.
His cough doesn't seem to be very productive at first, but often gets loose at the end and we've yet to see any coughed up phlegm.
During the night coughing he sobs and says it's scary, but once he recovers he's ok and goes back to sleep.

He's not thirsty, craves sweets, seems to be better outside in fresh air, worse at night/lying down. Gets stubborn when ill, often not listening to our advice when coughing (sometimes kicking and shouting 'he can't do it' instead of working on breathing and calming down. Likes to sleep covered up and often sweats as a result under his duvet. Else is very sweet, affectionate, loves company and cuddles. Very talkative and happy boy.
Any advice would be very mucj appreciated.
Thanks so much.