Well for the first the proper pilot position is always the starboard side in almost all helicopters! The co-pilot sits on the left.
Usually ambulance helicopters are flown with 2 properly rated pilots so yes there would normally be installed dual controls in a medevac helicopter.
Some ambulance helicopters are smaller than the Huey UH1 but civilian ambulance companies never use Huey´s. They would use the similar looking Bell 212 or 412!
Smaller types use only one pilot which flies from the right seat like the B206 or B407 helicopters, but they don´t look like Huey if that matters for your story. However if you are concerned that the scenario is a truthful picture of real life and you want to use only one pilot in the story you would have to use some civilian type helicopter like B206L or B407 for example.
In single pilot operations there are no dual controls installed so it´s higly unlikely that the son would be able to assume any resemblance of control from the left seat unless he was pretty experienced pilot.
The landing would have to be possibly a combination autorotation-run on landing since he would have no chance of reaching the anti-torque tail rotor pedals for directional control.
The fuel only explodes in Hollywood movies, seems that all helicopters that crash in films carry a small charge of explosives around. However the fuel could start to burn after the crash.
It´s likely that if the son has relativley could experience in helicopters for the sake of your story that he could steer the helicopter to running landing where it would roll over during the landing and he would carry his unconsious father out of the wrecked helicopter at the last moment before the fire consumes the fuselage... but please no explosions unless they are carrying ammuntion or fireworks.