My structural ingeneer want me to remove the inside portion of the icf to assure that I have a minimum of 8.5 inch tickness of concrete
to make sure that I have enough concret for my lintel. I'm got a use structural fiber in my concrete mix. For sure
he specifie some horizontal and vertical rebar for all the openings.

What is your opinion about that ?

How wide was the cavity you poured the concrete into? If it was more than 8.5 inches before you poured the concrete, you're probably safe.

It's over large openings (patio door & 6' wide openings ).
For the integrity of the wall, I should have a minimum of 24" height
and 8.5" thick of concrete over the opening.

It's more about the rebar schedule and less about the concrete thikness. Adding a 1/2 inch of concrete doesn't do much. Hopefully your going to use Helix fiber the additional stenghth of the concrete when adding 10lbs per yd. to a mix is amazing.

Sorry, I still don't get the point of removing the inside portion of the ICF. Did you pour this wall? If so, you should know how thick the concrete is.

I think he is talking about removing the inside foam so that a couple extra inches of concrete thickness will get poured in. A shame to remove insulation - is is possible to use a stronger mix or more steel in that area and leave the thickness alone?

Sometimes I not so bright (hahah). Add more steel for stronger lintel. Helix will help also.

That's What i thing, add rebar and don't remove foam but the engineer still
want me to remove the inside portion of foam so I can have more tichkness
of concrete to assure the strength of the lintel.

Is this a multi-story home? What is the load above that you want to support? Is it just the roof? Is the roof concrete or wood?

Maybe a small steel box or I beam.

It's a 2 stories home and the roof is made of wood

6' is not a large opening span. I would suggest talking to a differect engineer