How do you deal with it?
Basically, anything even a little bit 'heavy' is not up for discussion. Only Pollyanna, happy, happy type of talk is allowed.
Nothing serious is brought up, ever. If you bring it up, it's like you shat on the dinner table. For example, I have an uncle who (with hindsight) died of aids in the early nineties. Never spoken of. At all.
My parents divorced. My mother still pretends to people they are still together (e.g. when filling in a form she'll click married). He has a new wife and now teenage children. They are never mentioned.
I've just distanced myself from them. I find the 'make believe' very stressful.
One time I tried to address an issue directly, and I got gaslighting (that it never happened - the situation is something like mother is Greek Cypriot, but we never learnt greek. I said I wish we could have learnt greek as children and that would have helped connect to extended family. She said we did. We clearly didn't, and I can only speak it after paying for years of lessons) then 'sorry for being a terrible mother' followed by weeks of silent treatment, followed by pretending the conversation never happened.