weird brown spots
Please forgive me not being too specific, but it's my first post on this forum and, to put it gently, I am yet to become experienced at gardening
My friend has developed a lot of dark brown/red spots and became dark along the nerves. I thought that perhaps it's rust, but I don't know. Could someone help with what kind of infection it may be, if any? Can the plant be cured if most of the leaves have those spots?
I attached images of infected and clean leaves for comparison.