UK- US Does Bigamy invalidate everything?

[MerseyMan]

Hi there!
This is my first post and I'm hoping to get some advice from some of the experts on here.
Here goes:
My grandfather left my family in 1949, after lots of researching I found he ended up living in the US. He was given his SSID in California in 1954 and married twice in the US. My grandad was still married to my grandmother in the UK though. Through more research I found my grandad died in 2004 in Florida and left no blood relatives in the US, however he did have an adopted daughter from his first marriage and two step daughters from his second marriage. I am now in contact with his adopted daughter from his first marriage and my family, especially my mother get on well. As this adopted daughter from his first marriage is my mother's adopted sister does this have any bearing on whether I would be entitled to a green card or not, or does his bigamy invalidate everything?
It has taken my family about 60 years to track my grandad down but was thinking of staying in the US for a short while/maybe long term even before I knew my grandad had lived in the US.
Any help on this matter would be greatly appreciated.
Regards

 

[BigJoe5]

It would be a highly complex relationship to prove between your mother and her adoptive sister. First you'd have to figure out what the laws were where and when it happened. Then you'd have to figure out if the relationship is valid for immigration purposes.

IF (and it is unlikely) that the USC adoptive sister could petition for her sister (your mother), that alone would take maybe 10 years to result in a visa. Then only your mother's spouse and minor unmarried children could get visas with her. Then assuming you are over 21 or married or both, you would have to wait for your mother to naturalize as a USC and then petition for you. So, you could get a visa that way but it would take 25 to 30 years.

His alleged bigamy is irrelevant.