Why for the life of me I can’t stay awake when listening to Music?

Lack of exercise could be a contributing factor.  We all age differently but at 62 I wouldn’t call you old yet.  Go get a check up to make sure it’s nothing to be concerned about.  I’m 57 and can sit in my listening chair until the wee hours of the morning listening to music.

Might I suggest some cocaine? It’s a hell of a drug. 

Sounds like you have a perfect system. 

I am aware of a lot of systems that are hyper detailed and energetic. They make you want to listen to the system... the transient between an image and the space that separates it from the next instrument. You can feel kind of on edge because of the high frequency hash. I have had systems like this, and after 45 minutes I get bored and want to do something else. 

A system that allows you to drift into the music is a great system for me. 

How about trying some more challenging classical music?  Mahler for example.

It is OK to fall asleep when listening at our age, except when we are in a concert hall 

Well I'm 74 and walk my 10,000 steps everyday .Someday I go to bed early and some days I'm up till 2 am....