Yuna Hollander who also thinks her son might be gay, but is not as convinced as David, because she is the one who goes with Shane to nearly every single photo shoot and most of the ads he's filmed, and she has personally witnessed people of all genders and roles in the entertainment industry trying to flirt with various degrees of brazenness with her son and all had failed miserably. They were all met with the utmost indifference, David. Surely, if Shane is gay, there would have been a model or actor or hairdresser or make-up artist or light technician who would have caught his eye. And Shane is very polite and considered, but surely if he had been interested he would come up with some excuse so she'd have to give him some privacy and he could shoot his shot (he never has, but just in case, since trying to flirt with someone while your mom is in the room is weird, Yuna at least makes sure to come up with reasons to leave or avoid going at all as often as she can). Besides, David, we both know that boy can't lie to save his ass so there is no way he is managing to be all suave when someone he likes flirts with him. So, since he never shows the tiniest of reactions, Yuna's main theory is that yeah, Shane might not be into women, but it certainly looks like he isn't into men either.
And then years down the line, as Yuna Hollander is telling all of this to Ilya Rozanov, Ilya gleefully decides to clear this up, and tells her that well, you see, Shane isn't just super gay, he is also super bad at realizing when people are flirting with him. "In fact, Yuna, during the CCM shoot I had to..." And then Ilya never gets to finish that sentence because Shane jumps over a sofa and a table and tackles him to the ground to get him to shut up, shUT UP, ILYA, I swear to god I will divorce you right nOW.