If you can borrow €10k from relatives, you can borrow €1k first to take legal advice.
The landlord had to pay his mortgage and expenses while you were not paying rent due to him, so I can see why he wants his rent. He probably has his bank on his back. It is likely that you will have to get a judgment against you unless you can your solicitor or someone else to argue on your behalf.
If I was a creditor and I realised that a debtor was insolvent but was prepared to borrow half the money from relatives, I would grab it.
Do up a statement of affairs. Your assets and your liabilities and send them to the landlord. His solicitor will probably advise him not to spend money trying to get blood out of a stone. But if you just abandoned the property without discussions with him, he might be more motivated by anger than by good business practice.