I thought it was him because it kinda looked like him, and he was supposed to be around, but maybe he just showed up for the funeral. Idk.
I've no idea why he forgot everything. I suppose it's just the curse re-arranging his memory to make it looks like she never died.
I also wanted to know more about Misaki's family, her power, and everything. The OVA might answer some question, but I doubt it will be enough.
And don't feel too bad about your lacking power of observation, you're not the only one lol