I'm so sorry to hear that Woley, the only consolation is that your FIL is in hospital, which is where he really needs to be.
It's very difficult for you and your DH, but it has been really hard for you for a while, hasn't it? knowing that FIL was so far away, and refusing the support he needed. At least you know that he is being cared for now.
Speaking from experience with elders in similar situations, your FIL may actually feel relieved to be in hospital, he must have felt weak and distressed and may welcome that he has been taken in hand by professionals who will relieve his symptoms.
I have a memory of having to leave one of my elders in A&E in a very distressed state because of breathlessness and palpitations, and not very long afterwards [she was lucky!] finding her propped up in bed, calm, smiling, her hair neatly brushed, her symptoms controlled, and quietly accepting that she was exactly where she needed to be, though she was as fiercely independent as your FIL beforehand.
But it's a turning point, and a difficult one, and I wish you and your DH all the strength you need to deal with it. And I hope your FIL receives the best care he needs, and feels safe and secure where he is.
xx