Starry Knight

Lightbulb Sun album - Porcupine Tree, on the first song, his voice is making me sleepy, interesting so far though

Illinois album - Sufjan Stevens, was only okay in my opinion though I believe dad will enjoy a break from the usual artists in it so far

Ran into an older band, Cinderella have you heard of them? they seem right up my dad's alley

I haven't heard of Cinderella band. I mainly listen to Progressive/alternative rock and indie. Here's another one,

https://en.m.wikipedia.org/wiki/Mellon_Collie_and_the_Infinite_Sadness

It is regarded as one of the best albums of the nineties.

I will stop here now, give all of these a listen, I don't want to give "an excess of everything" problem. I hope most of these suggestions are accessible.

been adding a bunch of Floyd to my list, alternating between that and Bon Jovi currently

If I find any interesting Alt rock or indie I'll let you know though