My cat needs some help

Hi there, my name is Andrew, I am from a relatively small russian town Voronezh, I am 21 years old student.
May I have a bit of your attention,
Its been 5 years ago since I was a young boy, who lacked warmth and love, I might suggets its a quite common thing for many people, when you need an object to love. And I found it, it was pouring down outside while I was sitting in my kitchen and suddenly there was a tiny cat helplessly weeping outside,there was no choice for me but to take it home , bath and feed it.
Since that exact day I've been going to bed hugging my cat, whose name is Stepa, He didnt just become my cat, he became somewhat special for me, he is my speechless buddy, whenever I am in sorrow - he is near, when I am in just lonely he somehow feels it and makes me happy, and according to my parents he is always at the door waiting when I am gone.
But our dream was to be soon over, he has started suffering from a urolithiasis disease, he pees blood and has tremendous pains, while trying to act it ok in front of me.
He is struggling on it on daily basis which just tears my heart apart seeing him crying next to me, unfortunately the drugs that I can afford like "Kotervin" arent helping him much, and neither me or my family have money to buy him a proper examination and further treatment with much needed medicines, I am desperately trying to find a part-time job to get at least some summ of money, we arent a middle-class family unfortunately, my father is a security guard, while my mom is a confectioner at the factory, our small savings are already being spent on helping my buddy.
Everybody loses someone very dear throughout life, but it just makes me unbelievably miserable even to think about losing my best friend, I dont want to live without him and will try my best to save my buddy, I truly hope somebody who read my story would help me with my cause, I hope for your support.
Thank you.