Help for a friend

My friend has a 2003 concorde with a 3.5l motor and a few weeks ago the check engine light came on with a cam position sensor code but they drove it anyways (put a Used sensor in from the wrecker), a week later after that the fans always seemed to be running on HI and the gauge about halfway(so his wife says) he took it in and had a new thermostat put in and fluids changed (anti-freeze, oil) and the problem still exists i told him that it could be a coolant temp sensor gone bad but he doesn't want to listen to me but his wife is getting mad because her car is just sitting and is afraid to drive it due to the temp gauge sitting higher than normal. i told her if a mechanic flushed everything and test drove it and it didn't overheat on him it could very well be the bad temp sensor and that i would ask here and see if anyone else had this issue. They have spent 400 on it in the past week to try and correct the issue but if it is just a bad sensor i would help them change it out and hopefully get it back up and driving again.

Is there anything else i should check for them

car when cold the fans are off
car driven 30 mins the fans on high and won't cut out at all as the gauge is high

ok after i helped him change the coolant temp sensor he took it for a 30 minute drive everything seemed fine then as his wife went to goto work she barely made it onto the highway before she came home and said the car was shaking and didn't feel right and the temp gauge was almost at the hot line.....( oh it was boiling like a kettle Heard it for the first time)

now after they changed the upper rad hose
thermostat
flushed the cooling system and got the oil changed
changed the coolant temp sensor

Still sounds like a boiling pot of water after a 10 minute drive

Could this be a water pump issue or as i suspect a Head Gasket issue

is there any steam coming out the tailpipe or water in the oil? one quick check is let car cool off to ambient temp, take the cap off to equalize pressure, put it back on and start the car, let it run for about 30 seconds and rev it up a few times. shut it off and go squeeze the upper rad hose, if its real hard with pressure you probably have a blown head gasket. can also start it with cap off and look for bubbles in the coolant or if its real bad water will fountain off when cap is off and you start it