If a person is in coma &on ventilator because of severe lung damage, would drs try to wean him off even if he was still comatose?

Your post is somewhat vague. The fact that mechanical ventilation by itself has risks of lung injury will push physicians to attempt to wean any patient if their system responds by resuming automatic breathing. Many comatose patients can survive for months/years on no ventilator support. Removing a ventilator in that situation is a good thing.

The decision to curtail a ventilator is complex and far beyond to scope of this general medical education site. This could be based on the significance of the coma, such as the presence of severe brain damage or brain death, for example. A conference with his physicians would be indicated.