My 14 year old cousin has Huntington's disease?

HER BACKSTORY: her mother (who was my aunt's daughter, therefore my direct cousin) had Korea Huntington syndrome, which was diagnosed when she was around 25 (she showed symptoms around 18 already!). I'm 15 now and my "direct cousin" had a daughter at the age of 18 ( the one I'm talking about, who's 14 yrs old now )... My 14 yr old cousin had experienced a lot of horrible situations with her sick mother (she would send her to school with her pijamas and socks, she would threaten her with knives and even kick her out of the house in the middle of the night; she threw their dog out of the window out of the 9th floor).. And now you ask: but where is her father? He ran off and left them alone to start a new family..It took a lot of time to get my cousin out of that environment. But the court finally decided she was better off with her grandparents (my uncle and aunt). So basically I grew up with her and that's why to me she is my "real" cousin. Her mother committed suicide (last year).

HER STORY RIGHT NOW: so after all the suffering she had to go through that I mentioned above things started to come together.. She was happy with her grandparents, had friends and even started to see her father and hang out with her half sister and brother.. And suddenly at the age of 14 she starts showing symptoms of her mothers disease ( it is SUPER rare to be showing symptoms at such a young age and when the disease is confirmed she'll officialy be the youngest person ever in our country with the confirmed disease, it was previously 17 )... My father told me this so I can prepare myself: she has been very weak; she has some weird ticks (exactly like her mom); she started suddenly eating with her hands (like her mom used to) and she once repeatedly spit in her bed just cause she "felt like it"(EXACTLY like her mom).. When my dad told me this there was no doubt in my mind... She's sick... My ONLY cousin who I grew up with has a HORRIBLE disease (a few yrs ago I looked it up and started crying with the fear of my cousin ending up like this.. Not only is this GOING to happen, but at an EXTREMELY young age.. The people I saw were 40/50/60 and she won't even make it to 30... I don't know what to do..
My aunt lost her daughter and will see her granddaughter die with the same awful disease (my uncle is her 2nd husband.. The first one had the disease and curiously died 1 week before his daughter did).. I'M SO DESPERATE HER LIFE HAS BEEN COMPLETE CRAP AND NOW SHE HAS SO FEW TIME LEFT... All this time she's been in school to prepare for the 'future' , what future?? :'(
she doesn't know about the doctor's suspicions and I can't imagine how she'll feel when she finds out.. All my memories with her.. All the things we went through.. Help I'm so sad :'( I WANT HER TO HAVE A HAPPY ENDING! :'((