My grandpa likes to listen to old songs that are only on YouTube. He's not very friendly with technology, and he's more comfortable turning on music directly from his phone without internet. How would I download MP3 songs for him so he can listen to them easily?

I had a similar situation with my grandmother who loves old songs but doesn't know how to use YouTube. https://easytube.pro/ I found a convenient service that allows you to download music from YouTube in MP3 without registration. Then I transferred the songs to her phone, and now she listens to them without internet anytime!