Would have been/wanted

Hello, people

I was reading an interview with chester bennington's widow, Talinda, and stuck on the phrase said by her

"Rather than staying “stuck in despair,” Talinda says that interacting with Linkin Park fans on social media helped her through the early stages of grief.

“They were reaching out, saying how sad they were and how they didn’t think they could go on because Chester couldn’t,” the 42-year-old says. “And I knew that that’s the last thing Chester would’ve wanted.” "

This last underlined sentence confused me a lot because I thought that "would have + past participle" is used when one wants to speculate about the past, but her statement about Chester is clearly a speculation about what Chester would say if he were alive. I tried to google it and found that many native speakers don't take it as something unusual:

https://forum.wordreference.com/threads/if-he-were-alive-he-would-be” vs“would-have-been”.3387962/

https://forum.wordreference.com/threads/mom-would-have-wanted-to-do-something-meaning.2979738/

I also found an article in a grammar book written by Michael Swan (Practical English Usage) saying that this actually happens. Here's a screenshot, 3rd paragraph:

Does this rule refer to what Talinda said?

So, my question is: Can I change Chester's widow statement " “And I knew that that’s the last thing Chester would’ve wanted.” to "And I knew that's the last thing Chester would want" ?