If Dad is in Hospice on Medicare, does he still need supplemental insurance and Rx. coverage?

I agree with ACaringDaughter, do not cancel any insurance. For both my parents I kept the sup insurance and Rx coverage running until they passed.

Remember Medicare only covers a certain % of the care, with the sup insurance picking up some of the remainder. And there could be pain creams, eye drops, etc that aren't covered by Hospice but are covered by Rx.

I’m terribly sorry and know this is a very stressful time.

Don’t anything to reduce coverage.

Patients occasionally rally and are released from hospice treatment.

If he doesn't plan on any medical treatment, then no. However, be very sure that he is not on any expensive medication that hospice doesn't provide. You wouldn't want any surprises at this stage of things.

I am sorry that your dad is on hospice, I hope that you and your family use the services they provide to help ease your loss.
I pray that your dads passing is peaceful.