I see similar stuff to this happens to other people here as well, but I can't seem to find any definitive solutions through the search, only discussion.

So a friend of mine has been becoming lucid lately, and he says every time he's tricked out of it in a matter of seconds. For example, once he thought his mother was knocking on his door in waking life, so he woke up from the dream, but nobody was there. Another time he thought his girlfriend was waking up his body and he HAD to get up, and when he actually awoke she was still asleep.

I've told him to expect a trick but what it seems like is that in the dream its just a little too convincing. Very different from my experiences, usually my lucids just black out and I wake up. I understand how to combat that, but how does one combat subconscious trickery? I'm at a loss on how to help him now.