[JeanFred]

askplatyp.us is another experimental front-end on top of WDQS − it worked with a slightly reworded question: https://askplatyp.us/?lang=en&q=Who%20is%20the%20aunt%20of%2...

[thom]

That appears to still just be using 'relative' as a relation, not 'aunt'. You get the same results for 'cousin' etc.