Salt poisoning of bush

Hi all. 

I am new to this Forum. 

in summer 2016 I referbished my house and installed a water softener. It works using salt water blocks to clean the filter. There is a outlet of old salt water that should be connected to a drain. 

I recently found out that my plumber‘s Pipe work just dumped the old salt water onto the ground next to a large mature plant. 

Mir used to be very large and difficult to see through it. Now there is very little leaves and the ones that are on it look burnt. 

A neighbour looked at it and cut it right back. Said that it is the best thing and I need to buy some food for it. 

Anyone with any ideas of what products may help this h she survive?

Many thanks.