If you know the exact model of the PSU you can try to search it on ZeusBTC use the link below and type the PSU model or just PSU.

- https://www.zeusbtc.com/ASIC-Miner-Repair/

I tried to search on Amazon and aliexpress I saw only a few of them but no trust ratings yet. So I think this would be hard if you are looking for a PSU for this unit.
Try to ask him for a PSU unit model and try to search on Google if you can find a site that sells it post it here and we will check if you can trust that site or not. Beware there are lots of phishing sites or scam sites that sell any mining-related products.