Hello and Welcome to ‘Ask A Doctor’ service. 
I have reviewed your query and here is my advice. 
As per your complain it seems that the symptoms of swelling of lips  can be due to 
Allergic reaction causing Allergic 
Angioedema of lips....
It can be due to any food or medication while other causes can be allergic reaction to any skin cosmetic, 
soap, lip balm etc..
I would suggest you to consult an Emergency 
room or a  Physician and get evaluated and a clinical evaluation and investigations like blood tests for allergies like RAST TEST, 
Patch test, Food Challenge test can help in ruling out the 
exact cause of the symptoms and treat accordingly.
As he oy has single 
kidney taking any medicine without proper doctors prescription is not advisable.. 
Do cool compresses over the lips .
He can be advised injectable 
steroids and antihistamines to reduce swelling..
Hope I have answered your query. Let me know if I can assist you further. 
Regards, 
Dr. Honey Arora