Defiantly you friend can invest in bitcoin. But first let your friend pay his debt first because there is no assurance of short time profit. Bitcoin is just another form of money. If he interested in bitcoin then he can, advice him not to leave the job. He can put 5-10% of his salary if he can. If he cant buy much then he can be participating in bounties where he can earn ICO token and which can be exchanged to bitcoin later on. Before invest you have know about bitcoin. You have to keep patient with good knowledge, when how what to do.
Never invest in ICO before full analysis especially without reading the white paper. You can share your knowledge with senior or community members. Remind one thing in every community there is some people will say this coin, that coin will rise buy them.
Never invest people saying to invest you thats way you invest. make your own plan, develop your knowledge about bitcoin, blockchain, ethereum, difference between security and utility token, different cryptocurrency exchanges. You can watch video on youtube about it. And never invest all of your money in one project. Keep some money if market go downtrend at that time you can buy more, it will be minimize your loss. Though market now in dumb season but when the market recovers. You will be pleased with the results.