ISO: Choffee Chiffon Cake - coffee frosting question

Hello! Could you please help? My mother used to make this recipe. And, as much as I was in the kitchen so many times with her, I was not familiar with the details of this recipe.

My problem is the use of the instant coffee in the whipped cream frosting. I can't see how we could just "blend" the instant coffee and vanilla into the fresh whipped cream!

Does the coffee really blend? I keep thinking we have to dilute it with a little bit of water.

I plan on making this tomorrow for my sister's birthday, would appreciate an answer if possible.

Thank you!