I’m sorry to hear about your struggles, but it’s great to hear you are trying.
Giving advice about family dynamics is really difficult because as strangers, we’re unsure of the consequences of our advice. That being said, below are some things that come to mind.
If possible, perhaps you can take initiative and explain later. Buy an xpen or make a better setup so they can see what it’s like, then have a discussion with them after the fact. Sometimes parents say no because they imagine it being a lot of work, but when it’s already done, they are more accepting.
Another could be just doing all the work and just asking for the final “ok”. Find the better setup, explain what you’ll do, and ask, can I do this tomorrow. You won’t need to do anything. That may be more appealing.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.