Why has he never asked about any of us at all?

Three out of four siblings all attended martial arts classes together with a guy and were all friendly with him. After many years he is currently trying to pursue a relationship with our youngest sister (whom he only knows through us) but has never once brought any of our names up in conversation with her or asked after us at any time after fully acknowledging that he was our friend from back in the day. We all find this very odd. Why has he never asked about any of our whereabouts or what we are up to in life or anything? He and our eldest sister even liked each other back then too.
Why has he never asked about any of us at all?
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