You could go with an Antminer S5 in which you could purchase 2nd hand of those in this forums computer and hardware section. It requires 590 watts from the wall. The sad thing is, your not going to make much but if you start right away, you could get back your investment just before the halving (assuming you got it for a good price) and anything after that would be profit.
What he could also do would be to buy bitcoins with his local currency, then buy the miner with the bitcoins. This way what the miner would have cost him in fiat money is stable, and he will be able to profit from the price increase that has 99% of chances to happen after or just before the halving.
It would cost fiat though .... "local currency" if fiat money (in almost all cases) and he buys coins with it. That just means buying BTC with fiat instead of miner with fiat. But really it does not make that big of difference as either way he is spending fiat to get a miner in this case.
Also having there is not guarantee of increase. We hope and speculate it's there. But it's no 99 percent sure thing, investors know about it now so it's not like it will sneak up on them.
When I studied Economy, one of the first thing we learnt was that if the supply get reduced and the demand stay the same or drop a little, the price increase. The price of a Bitcoin is the price of how much it costs to produce. If you get two time less coins, price should get doubled, but you have to think that some mining farms will close. To don't have a price increase, you need that at least half of the mining farms close their doors after the halving. It may even be more but I won't do complex calculations here.