Get him to the Dr. He can take steps to help his depression,. It is true, extended unemployment can cause depression. Counseling would benefit him, perhaps even anti-depression meds.
He needs to get some kind of work, even if it's delivering pizzas, or being a volunteer at the Red Cross or stocking shelves at WalMart. He could attend a local community college for a 1-2 year certification/degree. The longer he goes without a job, the harder it will be for him to get one, b/c employers will think, "what has he been doing with his time?" But, a job, even a simple one like those I mentioned, he can explain that b/c work is so scarce right now, he had to do what he could for his family, but he is looking forward to getting back into the industry of choice. Employers understand that. This is advice given to us by professional career counselors in getting people back into the workforce.
In the meantime, be sure he is on a good routine, getting excersize, networking. Have him take St, Johns Wort, it is very helpful. Also, eating a handful of cashews a day helps with depression. It has been proven by a PhD's studies in depression/nutrition. Have him start networking at your local city council and attending the Chamber of Commerce networking meetings. Networking is one of the only ways people are getting hired! Have him start a linked in profile and look for contacts he has worked with and can refer him.
Here is a great article on how to survive unemployment:
https://www.ldsjobs.org/Static%20Files/ERS/Surviving_Unem...
Also, my church offers free career counseling to anyone, regardless of religion. They help with interview skills, resume writing, power statements, networking... It would benefit him greatly to get this kind of help.There is plenty of information and tips on the website, but going down and doing the workshop he will get one on on help. Info here:
https://www.ldsjobs.org/ers/ct/stakes---wards.jsf?name=th...
find a center here:
https://www.ldsjobs.org/ers/center/find_center.jsf
great tips to get hired;
https://www.ldsjobs.org/ers/ct/stakes---wards.jsf?name=jo...
As for your mom and sister, set boundaries. Heal yourself