It very much depends on this person's intentions and sense of responsibility.
I've known too many over the age of 25 who would go from place to place, one friend's sofa to another, and not seeing any reason to get a job or earn their own keep. Many had 'unconventional' ways of stirring up an occasional $10 or $20 when they needed it, but making no effort to gain employment until/unless someone who was offering them a place to stay had made it a requirement. I put one of these people up for a month back when I was in Ohio, and he put on the appearance of looking for work, found a job, and washed out in less than a month. Hard to do, because his own mother was a supervisor. I ran him to work and picked him up. He had no drug or alcohol problem, had some sexual problems, and held fast to the mindset that he was still 12 years old and that someone else should just house him and feed him. I became his mother in that short period of time. In the end, he moved back in with his grandmother.
Another was 35 and a drug user who also had sexual problems. He went from place to place to place, and had an endless list of reasons why he could not and should not have to work. My son felt bad for him and asked if we could put him up for a while. This friend of his was over to visit my son maybe once a week, and was asking as well, campaigning on his own behalf, and I felt very much 'put on the spot.' In what was the first--and so far, only--time I had ever lied to my son, I told him the front office was asking questions about whether we had a boarder in our apartment and that we could lose our lease if we let him move in. The neighbor upstairs had put him up three times for extended periods just to keep him off the street, and this guy put them through a lot, all the while not contributing to rent or any other expense. It was like he was back home, living with his mother.
I say all this because most people--Christians in particular--feel a moral compulsion to help others, and that's a very good compulsion to have, but you can't let guilt make the decision for you. Is this a person who has fallen on hard times due to an interruption in employment or some other run of bad luck (for want of a better term) that can't be attributed to being irresponsible, immature, or having an addiction that they're not willing to deal with? Do they job-hop, constantly losing jobs in the first 3 - 6 months by way of getting fired or quitting? What is their general attitude? Does it reflect personal responsibility or is it largely a 'persecution' complex, where they think God or society or the universe itself conspires against them because they have to work for money to live and nobody should have to do that? (Believe it or not, that's a growing movement that started back in the '60s, and a lot of homeless people get homeless because they won't abandon that idea.)
I wanted to comment on this one because I have a unique perspective on this issue. I've been homeless four times. Four. By the grace of God, I had a car each time, so I had a place to sleep where I was still behind locked doors and safe, and by the grace of God, I found a safe place for my son to stay, so I never had my child sleeping in a car at a rest stop on the highway.
The first time was the only time it was by choice, and that was three years before my son was even born. I decided to move out of Ohio and try to get work and an apartment in NJ. I got a job the day after I pulled into town, and not even having an address. I was shocked. I ended up in Wayne NJ. I was desperate to leave Ohio due to the horrendous employment situation out there. A McDonalds was hiring, as they had advertised it, someone to run the fryer--just pull the fries out of the oil and do occasional cleanup. They had to close the restaurant for THREE HOURS in order to take all the applications they were getting, and I was one of the ones who showed up. The person who took my app said that two hours in, they had received over 400 apps. This was the Youngstown/Warren/Niles/Akron area.
I had an old rusty pickup truck, and I bought two sheets of wafer board and actually built shelves and compartments into the covered bed of that truck that laid perfectly over the top of the wheel wells. Hinges, knobs, I even painted them. I was all proud. Down the center, I laid a pad, pillows, and folded blankets. I gassed up the truck, pulled out of town on August 25th, 1985, and headed for NJ. What I didn't anticipate was getting a job that quick with no address. I also didn't anticipate the horrendous housing situation in Wayne. So I had traded one problem for another, but I finally found a room to rent.
The other three times I was homeless, it wasn't intentional at all. It was three months each time, in the Poconos in PA, and in the dead of winter. I could tell more stories. I was also employed each one of those times. On the last time, it would have been four months except that the Salvation Army out there that was right across the street from my job would put you up for a month, so I spent a month there.
You have to ask yourself 1) What is this person doing to help themselves? 2) What is their general mindset and perspective on life, and is it one of personal responsibility? And 3) What are they going to bring into your house? Do they have major issues they need to deal with?
It's like the story of the drowning man. I'd jump in to try to save a drowning man, but the point at which you let go is the point at which there is no hope of saving them, and not only that, but they're pulling you down with them.
Help a person who had landed on hard times and needs a place to stay so that they can get their life going again. Do not help a person who refuses to help themselves and/or refuses to seek help with addictions (the big ones being drugs, alcohol, sex, and gambling), because in that instance, you would in fact be 'enabling' the very lifestyle that has likely caused the homelessness in the first place. If the second scenario applies here, refer him to Salvation Army or any other local agency/organization that provides emergency housing assistance to displaced persons. Most of those places will also suggest or even require that he accept treatment in the event that he has any of the addictions listed above.