Does anyone have any experience or close-hand knowledge of heart operations?

They’ve just discovered a second murmur in my Dad’s heart, and that one of his valves is calcified. My Mum is so busy with him, and he’s in hospital, so I’m only getting my information second or third hand, but I have been told that they are going to operate. (We don’t know if that’s this week, this month, or at “some point in the future”, but they’ve not sent him home yet.)

Does anyone here know what the operation might be for? My brother in law thinks it might be to add a stent, but we – or at least, I – have no information as to what the operation is to achieve. (My Dad’s 84, so any sort of operation is not the best news.)

Do you know what it might be for? Or how long an operation it may be?

Thanks…