I would tell him you are tired of having this statement thrown at you.
I would say Nope, that statement is a straight up lie. It is a dishonest attempt to justify your position. You are stating that Catholics do not study the scriptures daily and that we Catholics are incapable of understanding a word on our own and that we are blindly following and doing what we are told.
Tell him you actually agree with him, throwing around that number is meaningless (that’s why I never do it). But the door swings both ways, his bluntness is meaningless as well. In essence he just called you lazy, irresponsible and dangerous. He basically, said you as a Catholic are incapable of learning on your own. He is saying there is absolutely no way you could read scripture, on your own, and come to the same conclusion that the Catholic Church has come to.
The way I see it he has two options here.
He can deny what he said and say he does not believe this. Which in essence means he just admited that Catholics are capable of interpreting scripture and that their interpretation can be just as correct as his. Which now makes those differences in theology , he claimed is minimal, pretty huge.
His second option is to admit that he believes all Catholics are incapable of interpreting scripture. Which is absolute arrogance and nonsense. If he admits that, then you are basically talking to an illogical person.
Think about it the Catholic Church has some of the smartest theologians on the planet, still alive in our generation, who have read their way into the Catholic Church.
Just to name a few of the many anti-Catholic sola scriptura converts…
Dr. Scott Hahn
Dr. David Anders
And the list goes on.
Ask him what point he is really trying to make here?
If this is really his point. Tell him you are disputing his claim of sola scriptura and you would like him to call a Church council to settle the dispute between the two of you.
Don’t ever give these guys an inch and let them pick and choose from the Church councils or the Church fathers. If they want to pull one quote from a council or a father, outright ask them if they are picking and choosing what they want or if they believe everything taught in that Church council or by that Church father.
You see these guys know they have the upper hand. They know we have to mind our words and come across as good Catholics all the while they take these indirect jabs at the Catholic Church. Stand firm. Be nice but call him out on it. Make him admit what he is saying under his breath.