I have an inspection tomorrow and i’ve been told the house has insul-brick on the exterior.
It is my knowledge that some brands (if not all) have some asbestos issues.
My question is this, What should i be telling the potential buyer about this product without alarming them and potentially being a deal breaker ?
The seller has said he may pay for the siding to go over the insul brick or he may just take the cost of siding the house into consideration with the sale of the house.

It sounds like he is anxious to sell it.

Your client can have it tested if it concerns him. No other way to know for sure.