I too would like to welcome you to the community here at Beyond Blue.
I am sorry to read you have found yourself in this predicament. It must be tough knowing your Mum suffers from bipolar and now you are having your own moments of depression and anxiety. That is enough to deal with let alone having the added stress of your Mum selling the place you are renting.
Am I right in thinking the sale is dependant on you and your friend staying on and you are not happy with the terms of the new tenancy agreement?
I don't know anything about the issues with selling/renting/new agreements. Can you speak with the real estate people and ask if they can suggest an agency or organisation that will help to sort all of this out.
Selling anything can be stressful at the best of times!
I hope you and your Mum are able to talk about all of this, if not, do you have a mutual friend or family member who could mediate for you so you can try and sort all of this out.
My Mum has depression and other mental health problems and I am always feeling like I need to be careful what I say and how I act with her. I too have depression, so I do understand the awkwardness you find yourself in.
My Dr and counsellor recently explained to me again that I am not responsible for how my Mum feels and acts. I know it is easy to say that but harder to do in real life!
Hopefully you will find some answers. Maybe there is a Residents Tribunal or some organisation like that that you can go through.
Wishing you well in all of this. Cheers for now from Mrs. Dools