Your photograph shows how upset you are - ears back, feet braced ready to run, body stiff with nerves... Your humans are putting you through a really stressful experience. I only hope they are keeping the puppy under total control - on a lead, in a crate, never unsupervised if you are around. You need to be free to go, or to jump up on to a safe high place, at all times.
That puppy should never EVER be allowed even to think about chasing you...
Why on earth are they feeding you where he can get to the food? Is your litter tray in a safe place where you can reach it and he can't? (Dogs sometimes EAT cat poo - disgusting). Can you get to the litter tray without being ambushed by this excitable canine? Are you safe at night completely away from him so you can sleep without one eye open? Can you choose whether to be in his company or not? I can't see a house-line on this dog, which should be there to make it easy to restrain him.
Keep your nerve. Never run otherwise he may chase. Stand up to him. If all else fails, if you have a cat flap, you can just leave home....
Yes, you have failed to train your humans. Now concentrate on training the puppy. Rewards (purrs, rubs and attention) and punishment (swipes with the paw). If you do this properly you will be able to use him as a pillow eventually.
This puppy is not a brother. He is a very junior servant. That's the purpose of a dog in a cat's life.
Yours in great sympathy,