I did think it a little odd that that thread was merged and closed. Perhaps it’s because the answer’s more than likely exactly the same. It’s not unreasonable to ask for a direct response from T212 for clarity’s sake though.
The official help pages give an answer. Since this was updated only 18 days ago, it seems like we should rely on it for what will happen to fractional NVDA shares.
Fractional shares get split just like any other quantity of shares.
In the example of a stock split, if you own 0.25 shares of company A at $100 & it performs a 2-for-1 stock split, you will now own 0.5 shares of the same company at $50.