I want to start by saying that it would not be absurd to say that Hodr is the son of Odin, because there is nothing to deny or suggest, well at least so far.
Starting with mythology, in ALL versions of Norse mythology Hodr is described as the son of Odin, but that doesn't count much here, after all GoW is an adaptation with many changes.
You may know that Freyr went to Asgard a long time ago to try to seal a peace agreement between the Aesir and Vanir. Well, he somehow managed to convince some gods with his poetry, like Bragi and Sif for example, it is quite likely that Týr too, but only Bragi and Sif were illustrated. But Hodr didn't like this and ordered Freyr to be set on fire alive, which happened, Freyr was burned alive, and fled from Asgard to Vanaheim in a hurry.
Now things started to get interesting.
In God of War Ragnarök, when Freya and Freyr go to make peace, he mentions the time he was burned alive in Asgard, Freyr refers to Hodr as Odin's family, and what else would Hodr be to Odin? Exactly, son. See below:
Not to mention that the facial structure of the Hodr illustration looks like Odin's facial structure. See bellow:
