hi
Thanks for your query
i can feel your concerns
he seems to be dehydrated and exhausted
take 
ORS and pllenty of fluids and juices
donot expose  to direct sun
use a cap or white cloth on head when go out
put 
cold water on head in case of headache
he can use apainkiller after consulting doctor
i advise to use a sunblock especially when go out
steam inhalation  can improve symptoms of lung hurts
give him green tea and honey
avoid cold and soft drinks
wishing him a speedy recovery
Hope i have ansewered your query
i am available for your help 
regards
Dr.imran