Good advice.

Another suggestion could be: asking what what he thinks about having his new sister sleep in the same room as him, and also sharing the playroom with her. This way:

- He could live the experience of having a sibling even more (at his age, it should be good and fun having someone close to share night talk, or even just feeling less lonely)

- He won't lose his playroom, and he will learn to share his space and toys (very important skills)

I agree the way the mom frames this change is paramount, underlining the positives and downplaying the negatives.