Can the Wish spell be used to allow someone to be able to cast all of their spells at will?

In my campaign, the PCs have recently defeated a dragon and looted its hoard. In it, among some other things, they found a fully charged Ring of Three Wishes. Not knowing what it was, the party had their Wizard cast Identify on it and when he found out what the magic of the ring was, he lied to the party about it and ended up getting to keep it. Later on, the party set up camp and we ended the session there. Afterwards, the player of the Wizard came to me in private and asked if he could use the ring to wish to be able to cast all of his spells from now on at will. I told him that he’d have to find out by using the ring and the conversation ended there.

Is this something that the spell Wish could theoretically do or is my player just gonna be out of luck when he tries it?