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.