I got myself into trouble with Bank...

You may need some legal advice- can you afford to make an appointment at a local lawyers office?
Some lawyers firms offer free consultations and a few uni's also offer free legal advice from their law students.

But you are not liable for your brother's problems or any dispute that he has with paypal.
Firmly dispute all allegations that you have committed any fraud and don't make any comments or allegations about your brother.

So I shouldn't tell my side of the story to the bank? Like describe the situation of what actually happen and why I got that money on my account?

So I shouldn't tell my side of the story to the bank? Like describe the situation of what actually happen and why I got that money on my account?

Have you been asked to tell your side of the story by your bank?
It is your brother that has the paypal dispute not you, paypal can sue your brother is they are able to prove that he owes them money.

Money laundering requires a crime proven to be committed and that the money launderer be involved in an illegal conspiracy.
Receiving payment of a loan is not a crime- but it will be very helpful if you have kept the IOU dated and signed by your brother agreeing to pay you back the loan.

Wow, sorry don't know how to advise.

(Other than get a new brother.)

Hey
So I have my Barclays account put under review 3 weeks ago and I will have the final results next week.
My brother owe me money around £200, he has send me it to my paypal which I later withdrew to my bank acc.
Few days later Barclays put my acc under review. I have called them they told me not much but enough to understand that the problems lays with the money I received from my brother.
He finally admitted to me that he scammed some people on facebook marketplace and thats why he had money to give back to me. If I only knew that...
So since I withdrew the money from ATM this could go under money laundering or whatever its called.
I had zero knowledge that this money comes from a scam. Paypal has already issued a chargeback and my brother is on negative balance there, but I can't be bothered about it as my account is freezed for a month and most likely will end up in closure of the account and CIFAS marker...

This means I won't be able to open bank acconut in e.g. halifax, hsbc, santander etc for next 6 YEARS!!! crazy haha
I am still active student for next two years, guys what are my alternatives to have working bank account? To receive my student finance, make payments etc. I got no idea...