It depends completely on how they go about the refund.
If they have 200k bitcoins and decide to only offer cash refunds, then they have to sell 200k bitcoins, which will crash the market.
If they already have the cash and decide to refund in cash, then you have lots of crypto fans with a bit of extra cash in their pockets. That must result in extra buying, which would be good for the price.
I know that if I get cash, I'll probably put it back into bitcoin, if I get bitcoin, it will stay in bitcoin. The first is better for the price.
I'm guessing a good portion will want their settlement in Bitcoin (that's what I went for at least), but they are very careful to avoid any guarantees so far that this will even be possible:
it may be possible for Users to enjoy certain benefits such as the ability to receive bankruptcy distribution in Bitcoin (this matter has not yet been determined whether
distributions in Bitcoin will be possible, as the bankruptcy trustee is still investigating the matter).
So the extreme cases are:
1) Everybody goes for refunds in bitcoin, in which case $13 million USD pushes the price up.
2) Bitcoin refunds are not possible (which is more-likely because one stupid law is all that would take), in which case 200,000 BTC pushes the price down with a rebound when users buy back in with the refund cash.
I'm guessing in case 2 that they would try find a way to prevent a dip in the market like that (private auction instead of just selling at market value on exchanges).