Yaacov opening his eyes is in Sotah 13a. If you read Sotah 13a and you read there the meforshim on how it says Yosef was zoche to bury Yaacov and talking a lot about the topic, you see that Yaacov was actually buried.
No one is disputing that Yaakov was buried. It’s literally in the question posed to R’ Yitzchak, and it doesn’t bother him, because he’s still supported by מקרא אני דורש.
Yes, it says Yaacov opened his eyes and laughed when Eisov’s eyes fell out, and it’s something we can’t understand without the meforshim, but in no way does it prove that Yaacov was buried physically alive
Tosfos in Taanis uses that Gemara as another proof that Yaakov is alive (יעקב אבינו לא מת . . כדמפרש בסוטה גבי מעשה דחושים).
Some meforshim (those who DISAGREE with Rashi/Rif etc.) argue that Tosfos was only commenting on the הוא אמינא of the Gemara.
But if you learn Tosfos based on Rashi/Rif’s pshat, Yaakov opening his eyes is definitely a proof that he was physically alive.