Hello!:)
This question is about my cousin who has a green card issued year 1998, she has worked for a short time here, but she didn't found any job that she can pay her bills,
She was became sick and she returned in her country in 2004. Can she come back in USA , is any problem with that, what she can do?
Please send the answer. I wanted to help her if is possible.
Thanks:)

She will have to contact immigration in the US and see if she can get her green card reissued. Have her do that before she tries to reenter the country.

Hello!
This question is about my cousin who has a green card issued year 1998 and is valid until year 2009
She has worked for a short time here, but she didn't found any job that she can pay her bills AND became sick and she returned in her country in 2004.
Can she come back in USA ( she lived outside USA about 3 and half years) , is any problem with that, what she can do?
Please send the answer. I wanted to help her if is possible.
Thanks

Had you mentioned that the green card was valid until 2009 in the first place I would have answered differently.
Yes, she can come back but just to be on the safe side, have her call up first so there is no problem.