It's most likely nothing to worry about as its normal but as many responses have already said, if she already has an OB/GYN pay them a visit.
This is usually normal as long as it doesn't continue for very long. It usually is just the body stopping your period since it is now preparing for pregnancy. I don't believe its anything to worry about but i would still call an advise nurse or your doctor.
Definitley get checked just incase. But brown is fine, as previous poster said it's old blood. And at around 5 weeks there's implantation wich could also cause a tad bit of blood. Dont freak out and assume the worst, just call her doctor.
Brownish means old blood so normally nothing to worry about. Worry if its red (= fresh) blood. But no, there is nothing she can take for it. For some, it goes away on its own. For others it can last longer.
From what I know that's not a very good sign. Have her call her doctor as soon as possible. I hope is nothing to worry about.