In short, yes IT IS TRUE.
EGO is different from true SELF and EGO is created and overlaying SELF so as to FIT IN, and create the least issues with the SELF living in a given social environment, including of course parents and THEIR believe system... i.e. also their EGO.
So, YES, the EGO is there, essentially to protect us, defend us. If the EGO and its expression is too far removed from the ACTUAL felt and experienced SELF, trouble is bound to happen.
We get neurotic at best, some might withdraw into insanity at worst or suicide, yet another added form of defence. Suicide as a form of complete withdrawal from an un-defendable situation... if all those other defences did not work.
So, I happen to agree with your therapist, by what I have seen within myself - and of course with others... during therapy and mostly Large Group Awareness Trainings, I later on assisted with after I gone through them myself...
There are yet other experiences, like exorcism that pointed exactly the same way.
Axélle