My sister has MS and has left her family. Can a person with MS not know what they are doing?

Can a person with MS have irrational thinking and not know what they are doing?  My sister was diagnoised with MS years ago after a short period of time on meds she and her husband agreed that the side effects were too bad and she has not taken any meds since.  About a year ago her husband got mad at her which sent her into a panic mode and her family called the police because she was unconsoleable. They took her to the Mental ward. She was released in a few hours.  My parents and I live out of state and she came to visit us to get away.  While here she had several panic attacks, a night she spent with me she was unusally quite and had double vision but would not agree to go to the hospital.  Upon waking the next day she was better but had no memory of what she did all evening.  We are close and we talk on the phone at least once a week. Over the past year she has talked about MS episodes where she will have symtoms and not be able to think clearly, loss of memory.  One time she even said she drove the car home from a Dr apt but the Lord drove the car.  Over the past couple of weeks she has been upset and saying that her husband has been very hard to live with.  At one point they had an argument and she said she needed to plan an escape.  I suggested that she was fearful about what happened last year because the anniversary of the hosp visit was coming up.  Nothing she was saying about what her husband would I consider a threat.  She also began to go to parking lots to talk on the phone and during the conversations she would say someone is trying to hit the car, then she would move and say it again.  Over the past year she has suffered from sleep disorder and is on meds for that. I have received an email from her that was strange and full of misspelled and wrong words.  All this to say that last week she left her husband.  There was not argument just was gone when he came home from work.  Her husband nor children know where she is and she has not contacted me.  She did contact my parents and told them that my other sister (who she is not close to at all but lives in the same area and has now threatened her family with bodily harm if they try to find her and would not answer my call) was helping her and that she was going to move to our state but not live with us and get a job.  She has not worked in years because most days she can't even get out of bed.  Her husband has been primary care giver preparing meals etc.  A couple of weeks ago she had a sudden remarkable burst of energy so much so that everyone who talked with her thought she was high.  She was very cryptic in her last coversation to me but told me that she had gone to the doctor to get pain medicaiton for her back.  She told me she did not want anyone to know.  After reading some of the message boards about MS personality and parinoia I am thinking that that may be what is going on with her.