Purchase On Behalf Of Another Account

My client need to purchase a theme which he will not maintain. It need to show up on my account so that I can regularly update, contact with the support and stuff like that. How can we do that?

Is there any way he can purchase the theme from his account on behalf of my account.

No. everyone should to purchase item from his own account. So that they can maintain update and get access to the download and get support from the item author.