Actually, gknot, my dad warned me about going out with young men "just to be kind". He reckoned it was a risky strategy (for me) and I think he was right. He also advised me, as a man, that a straightforward "No!" was much easier to accept than a don't know, should I/shouldn't I, pussy-footing around sort of answer. I think he was probably right about that too, and being straightforward (blunt, even) probably means you're less likely to be pestered.
You can't help it that the young man died young. I don't think you did wrong or were unkind.