Parent took advantage of my post-coma vulnerability to borrow £3,000, now refuses to pay me back
I am a university student in the UK currently on a health gap year after surviving a medical emergency and a coma. At the time, I felt incredibly disappointed in myself for having to leave uni, viewing it as my own doing. I was severely emotionally down and desperately wanted to make my parents proud of me again. Because of this vulnerability, I opened up and told them I had managed to save £20k entirely on my own.
My parents have provided absolutely nothing for me financially since Year 11; I have always worked to buy everything I own with my own money. Ever since I came back from uni, they have restricted my housing space and forced me to sleep on the sofa in the sitting room. Despite only having access to the sofa, I still contribute £50 to £100 from my weekly wages for household food
Seeing that I had savings, one of my parents came to me a few months later. He does handy work and claimed he needed £3,000 to fund materials for a job. He explicitly told me that since I "wasn't using the money right now," I should lend it to him so he could avoid bank interest. Because I was emotionally low and trying to win their approval, I agreed. He promised to pay it back as soon as he was paid. He received his money from the job months ago, but he has completely refused to pay me back since January.
I resume university in September. To protect the rest of my savings from being targeted by them, I have locked the remaining money into a fixed-term account. Because of this, I am currently living off my wages and buying my uni supplies on credit to build my credit score, but I desperately need my £3,000 back to clear this debt before September.
What are my options for retrieving this money from a parent without causing a total household eviction before September?
Any advice on managing financial boundaries and protecting myself in a toxic household would be appreciated.