PS4 [ASAP] OVERWATCH SAVE DATA: How it can be saved from deleting PSN account

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Hello everyone, I have big problem. My little brother has account on PS4 with mother’s connected credit card. And now, he spent much money on Overwatch (actually, not only Overwatch, but anyway) buying loot boxes. So to return the money his PSN account must be deleted
Can I save his Overwatch account somehow, like all the skins, lvl, rank and all this stuff? His account is actually connected to Blizzard, but…I’m not sure, that his save data will stay there
So should I be relaxed with Blizzard connected account or I should copy save data from PS4 somehow?