Mental Disorder. Or anything else?

I'm a Software Engineer from Hyderabad. Actually It's my Grand Mother around 70 years old lives in a small village near Vijayawada. She behaves very odd sometimes especially with few people around her. She keeps constantly saying that they(those few people) did something suspicious against her and her house. She keeps scolding them very loudly and irritating them and even not behaving properly with my mother(her daughter). I'm not sure what actually her problem is, since she behaves fine with me and with remaining people. I'm very worried about her. She is not staying with us. She is living alone in her house saying that she won't come to our house. And the problem is her neighbours who constantly suffering with her words keep complaining and even they started beating her and we're helpless after hearing this (which made me to write this). Will you please suggest me a solution whether this can be solved by any treatment from psychiatrist or anything else? Thanks in advance.