Tnaks for your comments.
I was trying to understand the general picture rather than dive in with
possibly misplaced specifics as I was not confident I had identified the
real picture. Some tedious and lengthy investigation seems to point to a
different cause (the printer) than at first seemed.
The printer in question is a Brother HL-L2360DN (a non-postscript
printer) and is using the Brother HL5170DN laserjet driver as that
seemed a suitable match in the absence of an exact match. The
combination works correctly except for the sleep issue.
I have also tried to use the CUPS system with a brlaser driver matched
to the printer, but I have been unable to get that working. For example,
plain text all comes out as one superimosed line, and more substantial
composed text seems to simply disappear between the print queue and the
printer. I suspect that the CUPS/brlaser combination is failing when
trying to convert from postscript to laserjet. I feel that I do not have
the time for seemingly endless investigation so I use my earlier
laserjet setup which works as stated.