First, you need to know the hotel he is staying at and th ename the room is registered. Look for the guest servie number of the hotel on the internet - or call the hotel directly and ask them. It is the concierge’s job to do things like this.

You will need to bill it to a Credit Card over the phone and give them all the ‘correct’ information. They will make it happen. My wife did something similar when I was on a trip and magically a 6pack of beer iced down just showed up in my room with a romantic card.