When you say inflamed - what exactly do you mean - do you mean it's suddenly got red and sore looking or is it actually itchy/swollen?
I had an infected scar when I was about 15 weeks pregnant with this pregnancy - I pointed it out to the GP and she had a bit of a panic but it turned out it had just had an encapsulated bit of infection on the surface since I'd had the CS which everyone failed to notice (in my defence I have a really low scar - on my pubic bone, and enormous norks so I couldn't see it!) In that case I was given some antibiotic gel which actually cured it in five days! You have to put it on three times a day though. But she should be given that anyway because if there is an infection you don't exactly want to be cutting into it in a repeat CS for the risk of spreading the infection.
So I would be asking them how they handle to it if it is an infection.
However if it is merely inflamed there can be many reasons for it - scar dishinience is one (where the scar is breaking down but has not ruptured). One thing that can help is an ultrasound of scar depth to determine what exactly is going on down there, but it's not necessarily conclusive.
Most ruptures are silent (ie no-one notices till the uterus is checked after birth). But ruptures can happen at any time during pregnancy or childbirth (or indeed at any other point where your scar is stretched).
I would personally suggest is that she ask for more information - about why the scar is inflamed, and what the plan is - to be clear if a scar is about to rupture, it's kinda stupid to say the solution is to wait a few weeks and then do a cs, esp. if she is already 38 weeks.
But as others have said, a repeat CS is not the worst thing in the world, the worst thing in the world is losing or injuring a baby or the mother, so she really needs to decide what is best in her personal circumstances.