Help needed - is it possible to come back to USA with green card

My in-laws have been out of the country for 1.5 year and want to come back to US as PR using green card. Are their green cards still valid after being out of the country for long time?  Do they have to get a US visa? 

Thanks in advance.

所有跟帖： 

• Reply -863211- ♂ (679 bytes) () 11/25/2014 postreply 10:03:55

• Thank you very much! -NLF- ♀ (20 bytes) () 11/25/2014 postreply 20:36:46

• Your in-law may come back -mmjy2014- ♂ (1005 bytes) () 11/26/2014 postreply 10:14:45

• Reply -863211- ♂ (804 bytes) () 11/26/2014 postreply 13:07:55