Im not saying he will earn. Im just saying to mine first with his computer to familliarize how mining works. Before you invest 5k dollars on mining. You should study it first. Not just buy right away
It's not that hard. Most miners come with their own programs where you just enter the address of the pool and boom, you're mining.
Mining with your GPU is usually harder than that

As far as just mining to learn it I would suggest getting a stick miner if you are not wanting to spend much. I consider it much better then CPU/GPU mining. Some of the old block erupters are pretty cheap.