My father died in the US in 2002 and I had to go out at very short notice. I used Delta Airlines and they didn't have a bereavement airfare from the UK to the US (It happened in January so the fare was pretty reasonable anyway), but I had to get from Ohio to Texas which my relatives in the US arranged and they did get a bereavement fare for the the intercontinental flights. I'd never heard about it until then.
As for the leg room, as I'm sure you know I need the leg room, I get a letter from either my consultant or GP to confirm what I have and you just need to show it to the airline who should hopefully obllige. The front row seats are usually reserved for the disabled and mothers with babies. I'm sure they would accomodate your wife.
Condolences on your bereavement and congratulations on the pregnancy, how bittersweet.
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