Dear Dalia,
I propose that you make your patient 2 different formulas using Xiao Chai Hu Tang.
When he's NOT coughing, give him Xiao Chai Hu Tang combined with Bai Shao (white peony) and Gui Zhi (Cinnamon twig). proportions can be:
CHAI HU and BANXIA: 25% each
HUANG QIN, REN SHEN, ZHI GAN CAO, SHENG JIANG and DA ZAO: 10% each
BAI SHAO: 30% and GUI ZHI: 15%
Xiao Chai Hu Tang is very drying and not to be given alone for long periods. With bai shao you are taking care of not drying up the Yin too much.
When he is coughing, combine xiao Chai Hu Tang with:
JIE GENG, ZHI MU AND QIAN HU (instead of ZI WAN) each 10%.
Please do this for 3 weeks and let us know how he is. If during that time, he gets an acute illness or a fever, you should stop the herbs and treat according to the new pathology.
Good luck, Soma.