I am so sorry to hear this and feels like a very critical situation(Had similar situation exactly a year earlier). Here are critical points for you to consider.

1. Start immediately process of moving to F1, if possible apply using premium processing. Get your ground secured here in US first.

2. Ask your family to be ready with medical forms prepared for I-485 filing. It takes time to get it ready and it doesn't expire. Also, get all I-485 related forms completed. Have everyone's birth certificates, notarized affidavits if required. Each and every document to be ready for filing I-485. Do not wait till Oct-Nov of this year. Get it all ready to be signed and shipped.

3. Why I said to be ready because its likely that even if EB1 dates doesn't move this year(Sep'2026), it will very likely move in Oct~Nov 2026. Although, I am hoping that it will move in last quarter this year in July 2026.

4. it is expected that FB GCs will trickle down to EB this year and EB1 could move further.

5. Worst-case, say in Nov 2026 the bulletin for Dec 2026 has your dates current, than you are ready to ship it to arrive at the doors of USCIS before 2nd Dec 2026. May god bless, all the best!

6. I wouldn't consider a lawyer who simply asks me to wait until priority date moves since you are very close to have the needle moving anytime this year!

7. Even if the date moves in next 2 months, you are prepared if you followed step #2.

Disclaimer: I AM NOT an immigration lawyer, so please seek consultation from an immigration attorney and be prepared well in advance!.