R.D.
LMAO, my dad did that once... with his 4 DAY OLD, brand spanking new Suburban ;)
I believe he had it professionally detailed at an auto garage. The main thing is to dry out the fuse box; she may have to rewire the system; she may have to replace those parts. Take it to the dealership.
Best wishes to HER, that stinks ;)
PS... my genius dad has also completely submerged another Suburban under water. During a hurricane, he thought it was 'JUST a little puddle'... dad and brother had to climb out the sunroof and swim!! That Suburban didn't make it ;)