It seems from the history that your mother had bleeding inside the eye because of leaking blood vessels. The leaking blood vessels are called as new vessels or neovascularization
There are many causes for new vessels, the important ones are systemic conditions like diabetes
and conditions of eye like central retinal vein occlusion
First your mother needs undergo evaluation to find out the underlying cause for bleeding.
Treatment is mainly by intravitreal injections, laser and if not resolved surgery may be indicated.
With timely intervention, chances of vision recovery are good.