I am sorry to hear this.
On this point
He quite understandably has managed to understand the doctor's words much more favourably than I did
my husband’s consultant records all the meetings, including our questions and his replies, and we are given the recording to listen to later if we wish. The consultant does this for all his terminal/life-limited patients, because he recognises people process (or even hear) information differently when they are stressed. We have found it useful for avoidance (we can listen later), planning (what did he say about next step options?), checking something we’ve missed/disagree about, and more.
More generally, after living with this for several years (my husband has lived way past the span of his original prognosis), we know there is no single right way of coping. We don’t even have the same way as each other (I tell my family and friends lots, he tells his nothing), so are in no position to give much advice to you; all I would say is respect each others choices, which for us means I don’t push him to tell people, he doesn’t stop me telling my own circle - but I make sure they don’t ask him about his health too often, and he’s oblivious (or pretends to be) about all the small things they do when things aren’t going well.