Brisket in the Oven Question

This is kind of a BBQ question, so please bear with me.
A few years back, many folks here started cooking their briskets on the smoker on high heat. Getting good results without the low and slow.
For generations, my family braised brisket for the holidays in the oven at 350*, with excellent results.

My niece is doing Seder this year for the first time, and she's not much of a cook. She was doing brisket in the oven at 350 -- put forgot to put the cover on it. After 1.5 hours she looked in and all of the liquid had dried out. She added more and covered and cooked for a total of about 2.5 to 3 hours. She says the brisket is still not soft.

I think she just needs to keep it braising until the collagen converts. I don't think the lack of liquid will do much damage -- every bbq brisket I've done on the smoker was not cooked in liquid.
My wife thinks that the high temp of the oven cook will mean that the brisket dried out in the 1.5 hours of uncovered cooking, and nothing will save it.

Thoughts?

(I'll find out tomorrow what happens with the niece's brisket, but I'm curious to know what you all think about the process.)

The thing is she’s now made a layer of almost leather from the braising liquid drying off. I don’t know that there will be much coming back from that. Mistakes happen, I don’t think if you get it to a point of tenderness through adding more liquid it’s not going to be sliceable, it will probably shred but, it will taste fantastic anyway! Sorry, I don’t know what anyone else might offer but, someone else might have a better suggestion.