Full-metal Alchemist Brotherhood: Why didn't Edward use other better alternative over sacrificing his alchemy to get his brother back?

Question

In the pre-final episode: episode 63 - The Other Side of the Gateway, why didn't Elric use the following options:

1. Ling gives the philosopher's stone to retrieve his brother. The reason Edward gives is the promise that he and his brother made. But alphonse uses the philosophers stone in the battle against pride and kimblee. This implies desperate times, desperate measures have to be taken. Moreover, the philosophers stone is already made by sacrificing lives and there is no way to change that, so why not just use it?

2. His father, Van Hohenheim offers his life. The reason Edward gives is that he is not willing to sacrifice a life for another. This seems like a good and right thing to do, but in just a couple of scenes later, Van Hohenheim dies, so why not just use his life to get back Alphonse as he is anyways going to die.

It is just depressing to see Edward sacrificing his alchemy.

Answer 1

Basically because it would be against what the brother's promised one another.

Originally they sought to get the Philosopher's Stone to restore their bodies but after Lab 5 and learning it was made from Human Souls they promised to restore their bodies without taking lives. even if Van Hohenheim was going to die and was offering himself up it was still a life being traded for Al which to them would be no better than sacrificing people to make the Philosopher's Stone and using that to fix themselves

It is just depressing to see Edward sacrificing his alchemy.

on the contrary it showed his growth. at the end Ed accepted his limitations and that he had been relying on something that was never really his (The Truth). when Truth asked if he would be alright without Alchemy, Ed responded that he had his friends implying he would be able to overcome his limitations with the help of his friends