Regarding the medication: There may/will come a point where your DH will be unable to swallow pills. My mother was already at that point by the time hospice was involved, so we were given morphere DROPS that we simply put into her mouth. Maybe under her tongue, I don't exactly remember right now. (You'd think I'd remember, I was the one who was giving her the drops).
I agree with others who say that oxycodone isn't really all that strong, in comparison with morphene.
Like someone else said, Hospice should be giving you a kit, a box, that will contain all kinds of medication for your DH. They give you this kit to take home and use at home, and you administer the medication yourself. Again, like someone else said, at this point, there's no fear of an overdose. (edited to add, I think the kit was delivered shortly after we got my mother home from the hospital).
Now regarding the funeral arrangements. Please don't feel supersticious. Nothing you do, regarding talking to a funeral parlor, will cause your DH any discomfort or to pass away any sooner than he would've anyway. Maybe just give them a call, let them know you may need their services at some point in the future. They are usually EXTREMELY sensitive and easy to talk to. They will probably ask you for basic info, and you can take it from there, depending on your comfort level. I think by at least contacting the funeral parlor and just having a talk with them, you'll have one less thing in the back of your mind.
SO many of us here are here for you, in as much as we possibly can. I am awake, if you want to talk. I know we don't "know" each other, but I just went through this with my mother a little over a year ago. *hugs* to all of you.