No, you shouldn't file your son's return on your same TurboTax Online account. Never start another return by going back and overwriting everything in the return you just filed. This will replace your info, which means you won't be able to retrieve your return later. Please refer to this TurboTax FAQ below for how to start an additional return in TurboTax Online:
https://ttlc.intuit.com/replies/3288574
