Keep in mind that each diocese or archdiocese may have local directives, approved by Rome for that diocese. For instance, on the web site for the Archdiocese of Portland, the general norm is published, followed by the local directive in italics:
Color of liturgical vestments (see #346): Beside violet, white or black vestments may be worn at funeral services and at other offices and Masses for the Dead in the dioceses of the USA. Gold or silver colored vestments may be worn on more solemn occasions.
When selecting color for these occasions, it is important to consider cultural sensitivity regarding color, fabrics, etc. The use of these additional colors should be determined primarily by pastoral consideration and not personal preference. Blue is not an approved liturgical color.
So in our archdiocese, whether the color of the vestments used for a funeral is white, purple, or black is something the presiding priest or deacon would decide based on his sense of the pastoral situation, rather than simply wearing what he or the family personally happen to like. Neither black nor purple would shock me, but I’ve never seen anything other than white for funerals. OTOH, I haven’t been to a funeral where the family was Filipino or Hispanic, nor one in a parish traditional enough to own any black vestments. That could be the different cultural situation referred to in the local directive.