Technically he can, if he chooses to announce a national emergency on the grounds of the pandemic making people destitute. He does have the power to divert funds from one branch to another, for whatever purpose, just as Trump has by diverting money from the military towards wall construction. He doesn't need congressional approval, and the state of the economy is dire, so I can't say it would be completely unreasonable. I can see a scenario wherein funds are diverted from, say, the military, towards social safety nets and direct support.