Here is a supplication that elevates the status of your parent towards jannah:
May Allah reward you for being a child who is truly thinking of his or her parents after death and gifting them with this dua and with an act of aesale sawaab.
This dua is taken from Surah Al Isra (17:24)
||Waikhfid lahuma janaha alththulli mina alrrahmati waqul rabbi irhamhuma kama rabbayanee sagheeran
|Yusuf Ali 24:
||And, out of kindness, lower to them the wing of humility, and say: “My Lord! bestow on them thy Mercy even as they cherished me in childhood.”
||And make yourself submissively gentle to them with compassion, and say: O my Lord! have compassion on them, as they brought me up (when I was) little.
||And lower unto them the wing of submission through mercy, and say: My Lord! Have mercy on them both as they…