Hmmm... To me this is another situation of one woman not being supportive enough to another who was in a vulnerable position...
You could have chosen to show you valued her friendship and the connection to her son and your child, sufficiently to urge her to stay in touch with you... France is not the other side of the world !
I don't think you needed to allow her husband's racism to create distance between you and her , on the contrary, it was a situation in which you and your husband could have provided much-needed validation and emotional support, instead of politely sitting on the fence, while inwardly being concerned and shocked.
Perhaps if you both as a mixed race couple had been more assertive and made it clear such comments as 'monkey-meat' were not acceptable, the guy would have kept quiet and learnt what was not socially acceptable. You coud also have spoken to his parents to air your concerns! Why be passive in the face of such racism? In a situation where you cold have acted to make a differenc,e you didn't.
Are you writing now, however many years later, to suggest that other people ought to take a stance in such social situations?
With respect, surely we all have a moral duty to DO the right thing, and make the effort to make a difference, one encounter at a time, not just write to share a 'perspective'.