How would that work, though? He certainly didn't swallow whitebeard whole. Wasn't his body still there after they removed the curtain? I know the full effect of a devil fruit is granted just by a single bite, and the second bite won't give the power to a different person, so does that mean if someone bites off your finger, they can steal your power from you? Wouldn't someone have remarked on bite marks on whitebeard's body, anyway?
Also, imagine how chewy he must be considering he was able to withstand all those weapons.