RAID 0 stripes data across disks. This essentially lets you get the throughput of both disks combined, minus a little overhead. It's great for faster transfer rates, but as data is striped across both (or all, if you use more than 2) disks, each and every one is required.
If you had a 5-disk RAID 0 array, just one disk failing would irreversibly destroy the array.
If he doesn't care about data loss now then just use them as 2 separate disks again, job done.