I am truly sorry for your loss. I have always found that advice from an attorney to be boarding on absurd. Ask him how many people with a valid AP document has he known to be denied entry. I recall none since I have been a member here (April 2016). Travel is why they issue AP documents. Many, many people travel and re-enter the US via AP every day.
Bring passport, AP document, EAD, and receipt for the I-485. Personally, I would go. Do you want to miss this trip based on a fearful attorney's advice?