At my wits' end - two elderly cats, one with dementia

[Imissmy0ldusername]

I have two DCats, the younger (7yo Bengal) is so curious, but a bit scared of the other Dcat. The elder cat is minus most of her faculties. She can neither smell or hear the other Dcat. So when she's faced with Dcat2, she wants to fight the incomer out. But the problem is that Dcat2 is a feckin bruiser. If Dcat2 ever retaliated against Dcat1, Dcat1 will come out worst. Big time. We keep them separate, it's really hard work. Can anyone suggest something?

How old is the old girl, actually?

We think she's 18, Cozie. She's a happy sort, but I'd be much happier if I could integrate them. I don't think it's going to happen, which is a shame, as it means that I end up playing cat table tennis in the evenings, when they both want cuddles :)