🎻A pharaoh in pajamas in the middle of the night 🎻

R' Alter Yachnas, the man who played Pharaoh's mangan in his pajamas in the middle of the night 🎻 and many clouds in the sky 🎸 and fire, fire, hot, hot, and more
He fell ill and many children sang for his recovery.
He eventually passed away on Saturday night, and now some are singing for his soul.

I asked:
Is singing for his healing the same as singing Psalms for his healing?
Why didn't God save them and hear their prayers and songs?
Is singing for the upliftment of one's soul the same as studying Mishnayot for the upliftment of one's soul?
Do we have any authoritative knowledge about what it gives to the dead?

I would be happy if the rabbi had answers, even if only to some of the questions.