Hello My Brother Had A Brain Surgery In 2015, And

Hello my brother had a brain surgery in 2015, and now the fluid filled tumor and in less than 2years the tumor has reoccur even bigger and wide spread, during the surgery they had a shunt or stent placed in his head to drain out fluid if it re-occurs to avoid further invasive procedure. Now his vision has decline, he's having tingling feeling to his ears and he's currently on prenisolone 10mg tablet daily. My question is, is it possible for the fluid tumor to occur and spread so fast within the period of 2years? and how is the procedure done when using the stent or shunt? and what other percussions can he take aside from going under the knife for the second time?