He can advance easily/ his path is smoothly paved/ his future is assure
In the question: He is on the right path. He is on his way to success.
("Because my people have forgotten me, they have wandered in the paths of the world, to walk in paths not paved" - Jeremiah 18:11, and so: "The paved way is for the time when those who pass by it will be marked out in it by many, as a man who passes by his paved path" - Hiddushei Haritba Masekhet Erubin 22:11, And so: "And this one has a path paved with shame and a path paved with no stumbling block, and his path will not be hindered, and he will despise the torment of evil, for his path is paved with desire and the thoughts of the heart" - from Proverbs 16:17)
Translation
Expression (Hebrew)
דַּרְכּוֹ סְלוּלָה
Definition (Hebrew)
בְּהַשְׁאָלָה: הוּא בַּדֶּרֶךְ הַנְּכוֹנָה. הוּא בְּדַרְכּוֹ לְהַצְלָחָה.
("כִּי שְׁכֵחֻנִי עַמִּי לַשָּׁוְא יְקַטֵּרוּ וַיַּכְשִׁלוּם בְּדַרְכֵיהֶם שְׁבִילֵי עוֹלָם לָלֶכֶת נְתִיבוֹת דֶּרֶךְ לֹא סְלוּלָה"- יִרְמְיָהוּ יח טוּ, וְכֵן:"הַדֶּרֶךְ סְלוּלָה הִיא לְזַמֵּן שֶׁעוֹבְרִין בּוֹ דְּבַקָּעִי בָּהּ רַבִּים לַהֲדָיָא כְּאָדָם שֶׁעוֹבֵר בְּדַרְכּוֹ הַסְּלוּלָה"- חִדּוּשֵׁי הָרִיטְבָ"א מַסֶּכֶת עֵרוּבִין כב ע"א, וְכֵן:"וְזֶה יֵשׁ לוֹ מְסִלָּה כְּבוּשָׁה וּסְלוּלָה לֹא נִמְצָא בָּהּ מִכְשׁוֹל וְלֹא יְעַקֵּשׁ דַּרְכּוֹ וּבָזֶה יָסוּר מֵרַע כִּי דַּרְכּוֹ סְלוּלָה מִתַּאֲוַת וּמִיִּצְרֵי הַלֵּב"- מַלְבִּי"ם מִשְׁלֵי טז יז)