Did my mother die in sin?

Question:

I want to make clear why this is so important for me. It would be either way when it comes to a mother, but given how much I owe her, it is especially concerning for me. I apologize if it's a bit long.

I was born in Texas (raised there too). My mom raised me by herself until I was 17 years old. The reason my mom raised me alone was that she got divorced a few months after I was born. She married my biological father when she was 18 and I was born about a few months into the marriage (my mom got pregnant at 17 and hastily married my biological father). She divorced him in a little under a year, after heavy abuse. She left to protect herself and me. He was big and she was only a tiny woman. She received both a heavy concussion and went deaf in one ear from him slamming her into a glass cabinet, in addition to multiple lacerations and facial scars. Despite being an attractive woman, those scars marred her face permanently.

That was, from what she told me (and I believe her), only the final straw. There were plenty of other "incidents" before that. It's just that in that case, it nearly killed her. Had a neighbor not overheard what happened, she would have bled to death while unconscious.

My mom's parents were very devout Christians and had disowned her after she had gotten pregnant with me outside of marriage. She was without a home and now a single divorced mother with me still as an infant. She basically raised me from a car while she looked for any shelter for us for the next week. That was when she started genuinely praying again, something that she never stopped doing afterward. She raised me to always believe in and follow God as best as I can.

She worked hard after that to give me a strong education, and make sure I was taken care of. She was often working two jobs and, more often than not, was going to bed hungry and thirsty in order to make sure I got a complete meal myself (she tried to hide that from me, but it was always easy to see).

One of the jobs that she worked was as a waitress at a diner. It was extremely difficult for her, primarily thanks to being driven deaf in her right ear by my biological father and her first husband, forcing her to always turn her left side so she would hear them exactly. One day, she served a man at the diner who had sympathy for her and asked if she needed help. At first, she just wanted someone to talk to, but it eventually became a full relationship.

Five years ago, she got married a second time, to him. Despite him being several years younger than her, she loved him greatly and also saw an opportunity to get me into higher education, as he was financially successful. I still remember how happy she looked on that day, I had never seen it before, unless it involved me (proud of me, happy for me, faking it to make me feel better, etc.). She was happy for the next four years.

We didn't see any signs that there was anything wrong with her, but obviously, something must have been. My mom passed away unexpectedly in her sleep last year, at the age of only 40. My stepfather woke up and told me he found her still in his arms, but she had just stopped breathing. After everything she did and sacrificed for me, it broke my heart in a way that I don't think could ever be completely healed.

Now, I'm worried about her given some of the things that I've seen about remarrying after divorce being adultery (and divorce, in general, being wrong) and the fact that she died in her sleep. I'm worried that she was in sin when she died.

Was she?