I think so, "Mr. Trump means that Santa is not important to a boy at 7"
The following evidence from here is acknowledging it:
Trump tells boy that believing in Santa at 7 is 'marginal'
WASHINGTON (AP) — President Donald Trump and first lady Melania Trump
took calls from children anxious to find out where Santa is on his
gift-giving journey.
In one conversation, Trump asked a 7-year-old named Coleman, "Are you
still a believer in Santa?" He listened for a moment before adding,
"Because at 7, it's marginal, right?" Trump listened again and
chuckled before saying, "Well, you just enjoy yourself."
Mrs. Trump told a caller that Santa was in the Sahara. Several minutes
later, she reported that Santa was far away in Morocco but would be at
the caller's home on Christmas morning.
Mrs. Trump later tweeted that helping children track Santa "is
becoming one of my favorite traditions!"
The NORAD Tracks Santa program became a Christmas Eve tradition after
a child mistakenly called the forerunner to the North American
Aerospace Defense Command in 1955 and asked to speak to Santa.
First, Mr. Trump has asked:
"Are you still a believer in Santa?"
Then he has said:
Because at 7, it's marginal, right?
Apparently, Mr. Trump meant that Santa is not important to a boy at 7!