We cannot expect very high incentives from signature campaign as the income from it is very limited and low too but if he can save that income regularly then it can help him in reaching to a descent capital in future which he can utilize in trading and can become a full time trader and start making money out of it.
Yes we know that and even you are going to add some other giveaways and social media campaigns it is not really going to be enough. But it is better to had than nothing. That's why I'm trying to point out that he can use those profit for starting to trade with alt coins.
Yes earning from signature campaign can help him in building up his capital if he manages to save those earnings without spending them and once he reaches to a good amount he can use it in trading altcoins from where he can make good profits and will also help him in multiplying his bitcoins over a period of time.
Signature campaigns earning are safe but they will not give you 1 or 2 bitcoins per month and not even in six months. . I think you should have good skills and you can get your services redeem in bitcoins, that way you can earn more bitcoins.
If we just solely on a Signature campaign to make the bitcoin, maybe to reach 1 BTC we must wait for a year.