I wrote to Executive Lounges (which manages the Aspire lounges) yesterday and got this as a reply this morning:

"Thank you for reaching out to us. After investigating the contacts with Brussell Airlines, I found that your wife should have had access to the lounge. A Gold Star Alliance card would grant you access to the lounge when travelling with Brussels Airlines.

We have taken the liberty of sharing your feedback with the manager to ensure that our team exercises greater diligence when assessing guest access. We sincerely regret any inconvenience this may have caused your wife, and we reassure you that we will take measures to prevent a similar occurrence in the future."