No Contract/renovation Cost 4x Higher Than Expected

Location: Spokane,Washington
I am seeking legal advise. My girlfriend offered to oversee a remodel on my home. She asked, “why won’t you let me help you with this?”. My home was in disrepair and I am very sick. The state of my being is important to this story, I was on a lot of medication post back surgery, just moved from hospital to rehabilitation when we first talked. I was in shock, in pain, and cognition impacted by drugs. I had just been told I had cancer and have been on chemo drugs or receiving radiation since October 2025, continued on many medications, some of which have a big impact on my ability to process and think clearly.
My friend is a contractor with years and years of experience.
Eventually, right after they started the project,we had a conversation where I told her that I had $10,000 to spend, she appeared to be listening and nodded her head. She had hired two crew members and started in October 2025. The remodel was on a single wide mobile home.
Throughout the process she would ask if I wanted something she thought would be good and I would say, how can I say when I don’t know where we stand, where are we at? I never got a straight answer with most of the time just moving on.
She was there working with the crew and procuring supplies, working 5,6 sometimes 7 days a week. Not charging me a penny for her time and passing on all her contractor discounts. This was an at cost deal so it never felt right to pressure her and I trusted her.
Two weeks ago I got the invoice for $49,535.46. I do not have that much liquid, nor can I afford it anyway. I never in a million years would have put $50,000 into a trailer. I have a home in town as well as this 5 acres. Retirement is coming from the sale of properties. I had to retire early due to cancer treatments. I do not have enough $ for a good retirement and the sale of properties is what I will live on.

1.Do I have any legal rights with no contract?
2.Does she have any legal rights as the contractor?
3. Are there any industry standards that dictate the contractor must supply a scope of work and estimated budget?
4. Without a contract, can she force me to pay within a certain timeline?

Thank you in advance for any insights and/or steering me in the right direction.