Prayers for you and your family. A friend of mine went thru this recently...mother was 98...she just wanted to die! She did, quite quickly, once she was in Hospice. She had asked my friend and her husband to overdose her previously....of course they couldn’t...Essentially, isn’t that what Hospice is doing with Morphine? I don’t envy you your situation, but pray it resolves quickly. Seems like the pain issue could be dealt with somehow, though.
Not saying it has never happened but in general? No they do not do that. They give oral liquid Morphine under the tongue and absorbed faster through the membranes there. The dosages usually used are far below a maximum strength. My dad passed on just double the minimal dosage he was given and I looked up all his meds and he was a long ways from maxing out on it.