I just said the truth that my Dad had cancer and I went home to spend time with him and then take care of things after his death (1y gap). Kinda annoying how they still ask me that even 8 years later, but at least there is usually some sort of apology or regret after I tell them.
I don‘t know why it didn‘t work for you, maybe it only works on compassionate people and I got lucky. Good advice though, no need to be truthful in interviews.