Is it permissible to excel in knowledge solely to please one's parents? And does studying pharmacy fall under the hadith: "Whoever traverses a path seeking knowledge, Allah will make easy for him a path to Paradise"?

The son must strive to please his parents, and this includes academic excellence as long as it makes them happy and pleases them. For God commanded obedience and kindness to them. Pharmacology is one of the beneficial worldly sciences that Muslims are obligated to learn as a collective obligation (fard kifa'i) because it serves their interests. Knowledge in Islam is broad, encompassing every type of knowledge from which a Muslim benefits or by which he benefits Muslims. Seeking beneficial knowledge is among the desirable matters due to the religious texts that mention its virtue.