Having a source of income is a crucial first step in bitcoin investment. It does not only allow you to invest regularly, it also helps you hold your bitcoin stash for a long time without premature sales. I don't think that investing when you cannot sustain it would be very advisable since this is the beginning of bitcoin gambling. When a person invests without having what he's doing, he's only monitoring the chart to see that it has appreciated before he withdraws it. Appreciation may happen and depreciation may also happen. This is why long term holding remains the best and as a newbie, long-term holding won't be very possible when you don't have anything that gives you a source of income.
Anyone that doesn't have a source of income has no business investing in Bitcoin because he needs to survive first before thinking of investing, so on that note, what the said fellow needs is a job in other to take care of himself and his basic needs.
If anyone decides to invest in Bitcoin base on the fact that some money gets into his hands without him having a weekly or monthly income that he can get his discretionary income from, it will only be a matter of time before he falls back to his investment just to survive , so it's a terrible idea to go into Bitcoin investment or anything other investment without having a source that can sustain the investment on the longer run, because starting is easy but sustaining your investment is another thing entirely.