Smiling without reason. I am not exist.

Hello doctor my sister behaviour is very odd from last 3 months but from last one week she is smiling with no reason and whenever I asked something she didn't reply and after asking 5to 6 times then reply she don't know why she is smile. She said 1 week ago that her mind is like blank. Recently anything ask from her she never telling what happens to her. I am her with last 10 years no issues of any relationship but issues related to money problems. I am very afraid what happens to her. Is it relates to mental illness or anything else. I consulted with psychiatrist on practo but she said without talking to her she is unable to prescribe anything. I tried lots but my sister didn't ready for consultation. Please tell me what I do now. Can someone give me best suggestion or medication without talking to her. I am ready for consultation. One more thing from last 2 days she told to me think I am not exist.