How I would make it:
1. Make the arduino to send position to the serial monitor, for example:
x450
y500
or:
x450y500M/C,L/R ;move/click, left/right
2. check if window "Serial Monitor" exist
https://autohotkey.com/docs/commands/WinExist.htm
3. using ahk built-in application Active Window Info obtain class of control in which text with position is stored in com monitor
4. then in loop periodically parse the string using some string managment commands and save it into variables
https://autohotkey.com/docs/commands/IfInString.htm
https://autohotkey.com/docs/commands/StringSplit.htm
and so on, depending what other data will you be sending
5. use mouse commands to manipulate your cursor
https://autohotkey.com/docs/commands/MouseClick.htm