If she is a first time horse owner, there is absolutely no reason that he needs to stay intact and I would never breed one of my mares to him, nor would I recommend someone to breed to him. Absolutely not. If she can't handle regular horses, which takes years and years and years to accomplish, I will never put my mare in her trust for breeding.
I've owned horses for over 10 years and have no desire to have a stallion. I have the knowledge about horses, but stallions are completely different then your nice minded gelding or moody mare.
She's going to get hurt, And she's going to blame the horse for her own stupidity that could easily have been prevented.
The only thing they are seeing on him is color and dollar signs because of it. If you don't know anything about genetics, pedigree and horses in general, you have no place to even go near a stud.