"Mom no longer respects dad."
Translation:Máma už si táty neváží.
Well, the rule is much more complex. Firstly, it says "the first unstressed position", not always the second word of the sentence. Secondly, if there are more clitics in the sentence, they have to all go to that position in certain order. Thirdly, every rule has exceptions.
Here you can use both "už si" and "si už". "Už" is short and unstressed and so when it is close to "si" (also short and unstressed) they don't have a fixed priority.
For some longer adverbs like "někdy" you can only have "Máma si někdy" and not *"Máma někdy si".
How would you use respektuje? Mama uz taty nerespektuje? Does it also need si?