Actually -- Jesus Christ is the only door to Heaven that exists,
and the TRUE church of Christ has yet to be revealed.
If you have NOT personally made a genuine commitment
to Jesus Christ, what church you select to attend is irrelevant.
If you HAVE personally made a genuine commitment to Jesus Christ,
the church you select to attend COULD BE very relevant;
Especially if you are a new convert with little background of personal study of the Bible, or
if you don't really intend to study the Bible for yourself, and are simply looking
for a group to spoon-feed you Christian doctrine without wanting to check it out for yourself.
The International Church of Christ has long believed they have "the corner" on the Cornerstone.
Yet, they have been experiencing increasing "turbulence" in the waters in the past few decades.
You would have to ASK SPECIFICALLY, and investigate further to find out if the group your
friend belongs to are old school mainline Church of Christ, or
Boston Church of Christ, or Crossroads, or what.
Then, you would have to take what you learn of their specific doctrines and practices back to
the Word of God.
Then, YOU would have to decide if you can "live" with any "controversy" you might find
between their doctrines and practices and the Word of God.
Each of us is INDIVIDUALLY responsible to God for our decision of who we follow
FIRST in our lives. If you get that correct, you already have a guide to help you
with the rest. You just need to refer to Him and what HE has to say.