I interpret 'wilting' as something positive in this case.
That is correct. To "wilt", as far as humans and animals are concerned, is often used figurative simply means "to become weak or limp" for whatever reason.
Whereas for flowers and plants, the more literal sense of becoming weakened by lack of water or care, is clearly negative, in humans and animals, it is the context that creates the positive/negative aspect.
It was Ian Blake, however, who, without hesitation, gallantly rose and
greeted her with a kiss.
"My darling, you are absolutely ravishing,” said he. Penelope
practically wilted in his arms. It is amazing what a title will do for
a man. Adventures in America, 1883 By Dr. John Raffensperger, Prof.
and in the negative:
Ah! gone, brief hours of joy never forgotten; lilies of my loves, wilted by insipidity; my sad and happy songs, smothered by my regrets; now I cannot even cry, I can’t even sing; I need to be insensitive to the pains of my love. Absolute Equality: An Early Feminist Perspective By Luisa Capetillo
To wilt is not common and, as you see above, tends to be used rather melodramatically when used figuratively in a positive context with people.