Why would someone who is at his senses leave his beloved family? Any person going on such a one-way trip must either have no family at all, or must have a seriously disturbed relationship with that family. In any case, that person wouldn't have much of a reason to give them his money.
I disagree here. My family is very close-knit, yet I've had several brothers join the army. That's a very high percentage of being one-way, and at the very least, is a 4 to 6 year commitment to be somewhere other than where your family is. They still keep in touch with mom and dad, calling regularly, visiting several times a year - staying for a few days or a week when they can get time off from their jobs. Our get-togethers aren't stiff, awkwardly silent affairs, but the usual jesting laughing and talking about important things going on in our lives.
There's a difference between co-dependency and familial intimacy - despite being close, despite knowing each other well, that wouldn't keep us from going away for years or for life, if we thought it was the right decision to make - and we wouldn't be too troubled by it either. Lonely - yes, sad - perhaps, but that wouldn't keep us from making the tough decisions that we might feel we need to make. Naturally, it's different with spouses, and they wouldn't leave them for any longer than could be helped, because they have a partnership and commitment to their spouse.
Ofcourse, being Christians, it might make a big difference that we believe we'll eventually see each other again of one if us does die.
Also, throughout history, many people have left their families and journeyed to new lands to either pioneer the land, or just moving to an already-settled place to make "a new life" for themselves, or to take advantage of an opportunity to prosper. Sometimes they'd stay in contact through snail-mail. And not modern-day 'within a week' snail mail, but mail that took two or three months before the letter would get there, and two or three months back.
A Mars trip would have, at the very least, plain-text email that arrives at earth in less than half-an-hour (Curiosity was 12 minutes one-way communication, but depending on where Earth and Mars is, it can be as long as 24 minutes or as short as 4 minutes). In all likelihood, you can add in photographs, voice recordings, and probably full video recordings, which will take an hour to get there, your family can read/listen/watch, and then write/record their response and send it back within the next 48 hours. That is a huge leap forward than any other form of communication at any other point in history for settlers except for the last 150 years.