i see why people would say kokonoe's a "groomer" but he wasn't actually "grooming" yosuga per se. he was surely not raising yosuga that way. not only was he keeping him alive as emergency ration at first but it was easy to see kokonoe bearing sincere affections for yosuga later in the story. he only meant for them to be like a family.. which then just eventually took a different approach.
Grooming is when someone builds a relationship, trust and emotional connection with a child or young person so they can manipulate, exploit and abuse them.
so yea, i think it's different.
Kitsune no Yosuga