Tution fees

no..he is not eligible for 80C deduction..because grand son is not a relative to grand father..

80C [xvii] as tuition fees [excluding any payment towards any development fees or donation or payment of similar nature], whether at the time of admission or thereafter,—

[a] to any university, college, school or other educational institution situated within India;

[b] for the purpose of full-time education of any of the persons specified in sub-section [4]

SUB SECTION [4] [c] for the purposes of clause [xvii] of that sub-section, in the case of an individual, any two "children" of such individual.

2[15B] "child", in relation to an individual, includes a step-child and an adopted child of that individual;