With all the many languages I've used in my life, ObjC is actually my favorite to work with, especially with the modern runtime and features. I first used it in the 90's with NeXT WebObjects and was pleased to see it become popular again.
Be careful with this kind of thing. You're inadvertently making the FP community look bad. A more constructive and less pushy approach would have been to recommend an enjoyable FP language and explain why you think it suits the parent.
Lots of functional languages are just as warty as Objective-C, said the Smalltalker of over 10 years who also does Objective-C and is currently using Clojure.
I personally prefer Obj-C over almost all the fp languages I've tried. Clojure and Scala being the two big ones but I've also spent a little time with haskel and erlang. I don't hate them but feel like I'm being handicapped instead of helped. Scala was my favorite since I could do either oo or fp. They are all just tools and I shouldn't be limited.