Heavy lug on ford solenoid needs large cable direct to battery. This same lug gets the charging system wire to the alternator.

The other heavy lug on the ford solenoid needs a heavy cable to the large starter llug.

The large starter lug gets a 12 g or so sized wire direct to the small starter lug.

The wire that (in factory form) went to the small lug on the starter, now goes to th small trigger wire on the ford solenoid.

If your friend is trying to bypass the factory solenoid that is on the starter because the solenoid is bad... this is not the solution.

If your friend did this for what some call heat soak, he really most likely has a bad ignition switch, which cant trigger the factory starter solenoid reliably anymore.

The ford solenoid is merely a large relay.
The starter solenoid actually has needed mechanical function.