How long have you been working at this company? If your managers think highly of you, may be you should talk to them and request that you get moved to the country where you mother lives. If they do not have office there, may be you can find a different company in that area/country? It's a tough economy, so I can imagine that leaving your current job may be a big risk, but if being around your mothers means a lot to you, you may want to consider the option. I'm not sure which country or market you work in, but if it is at all possible, you can certainly arrange for your mother (and may be another family member) to come stay with you. It may give you psychological boost and will allow you to support your mother.

You also say that you are working long hours. You should consider talking to you manager about taking a day or two off every month so that you can fly where you mother is and spend some time with here. Of course, this option is valid only if your salary allows for frequent flights like that (or you are able to get your company to pay for it.) It won't hurt to get in touch with the management to see if they have some operations where your mother is. I'd start from there.

All money can do for you is pay your bills. When you're chasing jobs and making sacrifices to get ahead, you have to make sure you're not going to be by yourself when you reach your peak. Look at the things that bring you happiness or that have in the past. It's difficult to navigate in the rough waters of todays world, we need to work to survive and jobs are hard to find. Making sacrifices for your career is fine but be sure they are sacrifices you can live with.