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.
sorry, i sent the wrong one in my files. yeah the psa gyarados i mean. the strokes are still pretty similar