What does THE END look like?

My mom was told her cancer has spread and it’s terminal. She’s on a maintenance chemotherapy now. She said she’s in more pain than she’s ever been in. She called me today and told me the end is coming and I need to drive home. I lost my Dad to cancer 7 years ago and that was rough seeing. How rough is this end? I guess it’s a stupid question but I’m scared. My Mom is my whole world. I just want to prepare myself.