Liver Transplant Questions

Hello everyone. We got the unfortunate news a couple of days ago that my cousin is in really rough shape, just overally very sick. He's been in liver failure for over a year due to complications from his heroin addiction (hep c and cirrhosis). He is in end stages of liver failure and his kidneys are now failing and will need dialysis soon, they are currently hospitalized and fighting for their life. I am just trying to get a better understanding of transplant scores and tiers possible time frames. I was told he has a high MELD score (the abbreviation could be mled), and he is in top tier for transplant. Their doctors have told my aunt that if they dont get a new liver in 2 weeks then we have to start planning end of life care. They are having a big meeting with many specialists today, and I'm just trying to get basic information so I can be better informed.

My questions are: what do these scores mean? If they are top tier will they have a shorter time on the wait list for transplant? I've seen that you can be on a transplant list for years, will there be no hope if they don't get one in the next two weeks or does being on the top tier get you one pretty fast.

Thank you in advance for being understanding and helping me understand what is going on.