You can call them up and find out if they need people for such services.
Heading in the right direction. Good Job... ALL THE BEST!

Here are some Old age homes address and contact numbers:

Anbagam
Besant Avenue, Adyar, Chennai-20.
Phone : +91-44-24915047
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Anbu Karangal
No. 1/216, Vivekanandar Street, K.K.Nagar, Chennai-78.
Phone : +91-44-24925252
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Kaakkum Karangal
No. 11, East Mada Street, Thiruvanmiyur, Chennai-41.
Phone : +91-44-24401825
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G.S.Senior Citizens Home
No. 184, Mylai Ranganathan Street, T.Nagar, Chennai-17.
Phone : +91-44-24347127
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Help Age India
853, Poonamallee High Road, Thyagaraya Complex, Kilpauk, Chennai-10.
Phone : + ...more