Excellent result, and thanks for reporting back. So many people come to the forum to be angry when something has gone wrong (rightfully so) and then fail to update when the right processes and procedures are followed and the issue is resolved.
It usually does take a couple of days for things like this to be resolved although it can seem like an eternity when you are without things you really need.
In theory the airline are on the hook to refund any reasonable expenses you might have had to make emergency replacements of items in your baggage. I am not sure how well this airline will respond to such a claim and it has to be reasonable - so no claiming for Gucci suits, but minimum midrange clothing that you might find any normal retail centre shouldn't be an issue. If you are returning home claiming it might be assumed that you should have had access to other clothes at your destination.
Hopefully none of this will be necessary and your sister in law can just move on now.