Tagging our expert on autographs: @swolepoke
Based on the signatures in these two threads (one and two) I think it’s a legit signature, but I’m a noob when it comes to autograph authentication, so my word doesn’t mean too much in this case. 
Greetz,
Quuador
At first glance it almost looks good to me.
I can’t put my finger on it, but something feels off about it. Maybe it feels too forced? Or maybe I don’t like how thick and perfect the ink is. Usually there’s always on stroke where the ink is thin since Sharpies were used. I would need better pictures of the pen strokes.
possibly could it be a new sharpie? i know theres a lot of inconsistencies like how using a worn out sharpie produces rounder lines etc. New sharpies always seen sharp
Possibly, but even then I’m still not a huge fan of it. Something about it doesn’t sit right with me. I’m not a huge fan of some of the letters as well as the spacing on the Kanji part.
I would need cleaner photos of the autograph to better determine.
The sketch is fine-ish. Again something just feels off to me.
Overall I don’t feel great about this autograph. I don’t like a few of the letters, the spacing in a few areas and the ink looks too clean to me, like it’s oil based not sharpie.
I summon @Alec for a second opinion!
I would recommend asking why his brother had a signed Sugimori card. Was he a Worlds competitor? If so, and if they can point to when he might have attended Worlds (it would have been a family affair after all), it would add a lot of confidence.
Worlds 2007 was held at Hilton Waikoloa Village in Waikoloa Village, Hawai’i, which is on the Big Island. I would expect the mother to remember if they traveled for a Pokemon tournament or not. Hoping that OP can gain clarity!
Thanks for the tag dude!
The more I look at this, the more I believe this isn’t real, but it is one of the best attempts so far. Great proportions and pikachu sketch, and a great card to practice with as it’s still cheap. There are a lot of big issues with it that I won’t point out so as not to empower the next attempt.
It’s at least questionable, but I think it’s a forgery.
Borderline thinking it could be auto pen. The photo of the light reflecting off the card makes me really think the ink isn’t a Sharpie.
ill ask for better pics, but i do think its a new sharpie.
Well regardless of that, Alec is one of the few other people in the hobby I trust for a second opinion. If he feels off about it, then that further confirms things for me.
It’s possible it’s real, but it would need a heck of a lot of provenance. Hopefully OP finds competitor swag, pictures, promos, etc to help support it if so.
Doesn’t look like sharpie to me. Doesn’t sit on the card like I’ve seen on others and is too sharp of a point.
sorry, i sent the wrong one in my files. yeah the psa gyarados i mean. the strokes are still pretty similar