How do I respond to my professors email about recommendation letter? He is out of the country for sometime and his FIL is ill I have contacted my professor about recommendation letter for my applications to PhD programmes. He has provided letters for few of my application. 

Right now I am applying to few more universities and have contacted him again to provide few more letters in support of my application. He responded by saying that he is in a different country and his father-in-law is ill. He said he would provide the letters once again when he is back in the country. How should I respond to his email? I feel bad about constantly bothering him about letters of recommendation.
Just say thank you and send best wishes for the health of his father in law. Nothing more is needed. 

Three is no need to feel bad about your request. It is perfectly normal and natural.