What do you mean "Use of 3270 is impossible"? You can access the mainframe via a 3270 session, or you can connect via telnet into a Unix System Services session. Based on what you've said so far, give up the idea of doing this. Mouse clicks can -- sometimes -- be used by a 3270 emulator, but without using a 3270 emulator there is no way for a mainframe to know the mouse button was clicked. Furthermore, you don't use ISPF (for example) without using a 3270 emulator.
Your request is not possible based on the parameters you have provided. Period.