Trouble coping with my mums depression?

Don't take this the wrong way but she might be psychotic. Psychosis is where people have delusions (thinking songs are about her) and paranoia (thinking the neighbours know stuff about you) and can happen in people who are severely depressed. Get her to a doctor NOW and tell them what is going on with her. Psychosis is highly treatable and doesn't necessarily result in a trip to the hospital. But it needs treating soon so go to the doctor as soon as possible. Hope this helps :)