You were very nice to your friend and what goes around comes around. As far as gifting a gun in most all circumstances, I would recommend a gift card at a local gun store.
Let your friend or relative go through the same process each of us went throught when we buy a gun. I have friends who I don't know everything about or all of their past.
I assume your friend was a very different situation and you used good judgement in this situation. Please do not take my above comments as any sort of criticizm vs. just a thought for others to consider.