I made a texture pack for my map and pasted it in the map's save folder. It works for me as intended but when my brother joins to my map via lan then it doesn't work for him. Any solution for this?
Either he needs to install it normally or else you need to set up a proper server with proper hosting for the resource pack so that it downloads automatically. You might be able to do that via Hamachi or Evolve, but I've no idea how. That's a question you should ask in a Server-related forum.
I know that doesn't really help you, but hopefully it points you in the right direction to get some help.