memoryRadio

https://www.youtube.com/watch?v=9o_G331bJvI

I tried searching the repertoire of American groups Chicago, BS&T and Ballin' Jack, but nothing.
Maybe I was looking wrong.
Or someone completely different plays and sings the original. Do you have any tip?

I can also add that the English original was probably created around 1970, the title of the original recording
may have the word "sister" or "love".

I wondered - could it be a song from a musical?