Estate being left to wife question

Wife's biological father passed away a few months ago. They weren't close, but he left her everything, she just found out today.

We are in Hawaii, her father was from Croatia. To complicate it more my wife is currently pregnant and 34 weeks along, making going to Croatia to handle this impossible.

Have tried to contact the military base legal office to get an appointment, but they are booked solid for the next few weeks. Will be a while before we can get in.

Don't have a list, but there is property/house/etc.

She has an aunt there that is willing to handle the matters via power of attorney, as far as what we need to be doing though, and any crazy taxes or other issues we should consider with us being in two separate countries.

Also how does it work with being taxed back here stateside?