change tool commend with button

Have a look at mdi_command as in this example (instead of 'net coolant-flood => halui.mdi-command-00' you would connect it to the button hal pin):
forum.linuxcnc.org/qtvcp/54583-call-cust...om-gui-button#315402

I'm sorry but I don't understand why and when you would need to push a button during a programmed tool change.
Usually a tool change in gcode defines the T word (eg T3 M6) and your python remap would then handle the ATC tool change.

Unfortunately, I remapped M6, and in my Python code due to certain reasons, I cannot use mdi mode.

Not sure what that means but in a remap you can add command to the queue like this:


[edit]
Are you maybe confusing python remaps with the python interface?
linuxcnc.org/docs/html/remap/remap.html
linuxcnc.org/docs/html/config/python-interface.html

The python interface cannot use self.execute() that has to be done in the remap.