No, I do not think that you can stop treatment on your own. You may choose to take a second opinion if you wish.
Shunt related infections are difficult to eradicate and therefore may need antibiotics for longer. Some times the shunt may need to be changed.
Long term Vancomycin may have some side effects but that chance has to be taken.
Usually shunted babies have a reasonable developmental outcome. However, shunt infections and repeated shunt changes may affect outcome.