How can I encourage my half-Jewish friend to research his Jewish roots?

Yitzhak K asked: I am 100% Jewish. One of my best friends has a Methodist mother, and a non-practicing Jewish father. My friend says that he identifies as “Agnostic”, believes in G-d, is not interested in practicing any specific religion, but occasionally attends church services on Sundays, and sometimes goes to High Holiday services. My [...]