Participant's spouse will retire in July, and as I understand it this is a status change that would allow the participant to drop the spouse from family coverage before next open enrollment. But, spouse is offered his own insurance now as part of the retirement package even though he won't technically retire for a few more months. Does participant have to wait until July to drop spouse?

Is the insurance for the spouse something that is recently offered, or is it something that he's been offered in the past and declined?

Yes, the spouse's insurance coverage has just been recently offered as part of his retirement package (although it's being offered a few months before retirement actually takes place).