It Had Been the First Time in Two Months 

I recently visited my parents’ house for the first time in a long time, and while I was there, I met my grandparents, who were also there.* My grandmother looked fine, but her dementia had noticeably progressed. If I have the chance to visit with her soon, I would like to see her again.**

Hi, Tanaka. Good job! Whatever changes I made were to allow your sentences to sound more natural to my native ears, to complete your thoughts, and for ease of reading. I hope that this helps you. J.

*Although most people will understand when you write “return to my parents’ house,” I think it better to use “visited my parents.” The reason being that you are visiting them, not their house, they, not the house, are the purpose of your visit. That they live in their own house is expected and understood. Similarly, we return to where we live, or work, or belong. Their home is no longer your home even though you were raised there. Yes, you are always welcomed there, but you now have your own home, the one you return to. However, if your parents' house is not lived in, then you could write about it as you did: “I recently visited my parents’ house for the first time in a long time, and while it has remained empty since their passing, as the site of so many of my childhood memories, I simply do not have the heart to sell it.”

**Sadly, my mother also suffers from this condition, so I understand how difficult it is to deal with. While her medication helps to some degree, alas, her mental condition continues to deteriorate. Please accept my sincerest wishes for you being able to visit with both your parents and your grandmother again in the very near future! 

For the first time in two months.

最終の文は変です。未来についてですか？それば。。。

"I would like to go see her again, if I have time."

OR

"I would like to go see her again, if I can find the time."

I like this expression better.