We are the only Christian denomination that doesn't believe in the Trinity like Mudlims do too, maybe thats what your friend had in mind - yes, you're right. He also had in mind Muslims don't believe in idols, too.
But, still, how can *not* believing in the trinity or idols or christmas mean that 'they believe the same as us'?
It's absolutely ridiculous, a comment from a mind which cannot reason properly