When I first met Thomas, I had bigger worries. Zombies, world of supernatural, all that.
But I did notice Harry trusted him.
When I first saw them interacting with each other, my first thought was 'brothers'. I had to remind myself Harry didn't have any siblings, so my thoughts turned to 'lovers'.
It wasn't all that crazy. They were totally at ease with each other, bantering with familiar affection that only happens between people who are closer than just roommates.
Of course, that turned out to not be the case. But, privately, I still think of them as brothers sometimes.