There is no specific power relating to this, so it falls into the general category of "nothing to say you can't." As you're not directly involved, you can use your power under S137 (assuming you don't have GPoC) to provide funding for this. On this occasion, the applicant has been open with you regarding the purpose of the grant, but you may already have provided funding to others for events that included the provision of alcohol without being aware of that fact.