If he joins up on the forum, I'd be glad to help.
What I've been doing for these types of requests now is to send an invoice for all items, not including shipping. People sometimes will also ask for a "quote" and I no longer have time for that. So if people ask for help, they need to do the math on their own (generally add the listings up, lol) and all I will do is to send them a detailed invoice if they generally understand the cost of what they are asking for.
Once paid, I order the items and then send the shipping quote when in hand.
In the past I would do this in good faith but I have been burned too many times on people not paying that I'm not willing to do that anymore and frankly I am not able to make as many trips to the store to return stuff.
Hopefully this of help to the person on reddit, but they need to be a member here if they want help.