"I believe the Scriptures say that in these last days he has spoken to us in/thru his Son.... If the Head of the Body cannot directly communicate with the Body we have a weak, sick, handicapped Body."
Now he is referencing as you can tell, Hebrews 1:1-2.
Here is what that text says, (ESV) Long ago, at many times and in many ways, God spoke to our fathers by the prophets, but in these last days he has spoken to us by his Son, whom he appointed the heir of all things, through whom also he created the world.
Simple questions here:
What is then tense of Spoken, I would say past.
Did God speak to your fathers by the prophets? Unless you are Jewish, No.
Did the author of this text mean for it to imply that Christ is actively speaking to the people via special revelation? I Would say no, and here is why --
According to Vincent's Word Studies, the literal greek rendering of the phrase 'in these last days' is "at the last of these days." Notable Commentator John Gill says about this -
[...] the Alexandrian copy, the Complutensian edition, and several other copies, read, "in the last of these days": perfectly agreeable to the phrase באחרית הימים, used in Gen_49:1 to which the apostle refers, and in which places the days of the Messiah are intended; and it is a rule with the Jews, that wherever the phrase, "the last days", is mentioned, the days of the Messiah are designed: and they are to be understood not of the last days of the natural world, but of, the Jewish world and state;[...]
Clearly the time period of Christ was the 'last days' for the Jewish nation and for temple based Judaism with the destruction of the temple in 70 AD.
The question that should follow in our minds then is, Does this passage speak of direct personal special revelation from Christ to all individual Christians, or is it speaking about God's revelation of the Gospel through his son? Given the direct context I would submit that the later interpretation is more accurate to what the author had in mind when writing this text.