Not true in any way. Your lawyer meant something specific for your situation. Since your family was moving out of the country, you are not required to file extension of stay for them and your lawyer has meant that they are not eligible in that context. However it is essential to file extension for H1 because one needs to extend the work authorization too in addition to extension of stay. In case of H4 holders, extension merely means their stay gets extended in US through a new i94. That doesn't mean that they are eligible for H4 at all. They can get the H4 stamped at a consulate using your H1 approval and enter US without any issues. Also tons of people have valid H4 stamping and live in India. Or go back to India for an extended period and come back later all the time.
You should read up and correct yourself on this topic.. Already you provided the same wrong information in the below link and continue to do the same even after someone personally clarified that they got their H4 visa without any issues for similar Canadian PR circumstances.
https://www.canadavisa.com/canada-i...-a-h4-need-urgent-advice.467557/#post-5786993
In the Avvo link provided in above post, an attorney has clarified that too.