Hi iris,
I have no magic cure I’m afraid! Teething can be really tough on the little ones (and on the mamas too!) My eldest suffered really bad with his teeth and whenever any came through his body concentrated on that and would always get some other ailment at the same time as his immune system was lowered.
My youngest has had an amber teething necklace form very early on and he hasnt had much trouble with his teeth. http://www.myriadonline.co.uk/products.php?id=1371&name=Baby’s Amber Teething Necklace
No advice on the cough though, as hard as they are to deal with coughs are doing a job and suppresing them makes it worse in the long run.
Lots of cuddles and comfort is probably the best advice,
Hope he’s feeling better soon,
Michelle x