

Ok, I have been in this situation. I was the crazy schizophrenic neighbour.
This does not go well for you unless you avail yourself of every avenue to protect yourself. This person is mentally ill and their illness causes them to have delusions about your brother and your family. Whatever they are hearing is making them think that they need to react by terrorizing you. In their mind they are protecting themselves. It is very possible that this escalates to violence.
You need to communicate regularly with the police and ask if there is a community mental health liason officer who you can be put into contact with. You need to keep a journal of every communication back and forth and every action the neighbour takes against you. Over time keep building a case until you can have the police detain them under whatever mental health laws you have.
You also need to supply a constant stream of documentation of the behaviour to your landlord. They can take action to preserve their property in the face of a mental illness that very well might burn it down.
I’m really sorry this is happening to you. Feel sorry for your neighbour if you want but advocate for yourselves and your needs first here.
I put Ubuntu on my year old Windows laptop and to my surprise, everything is just better. I mean better than Windows AND better than Linux ever was before when I used it previously. I wouldn’t be surprised if we start seeing some major manufacturers shipping PCs with Ubuntu pre-loaded in the coming years.