Marriage certificate question

[swarrier]

I am a US citizen and am applying for GC for my parents. My question is - is their marriage cert. a must for applying? They were married in the 60s and it will be very difficult, if not impossible, to obtain one at this stage. Also, since they are visiting me currently, can I apply for adjustment of status instead? Does that speed up the process?

Any info is greatly appreciated.

[knowledgeable]

You can ...

... have other documents like an affidavit from a friend or a relative who attended their wedding.

AOS while visiting is technically illegal as the intent was to visit not to file for AOS.

I would not advise further herein, but you can surely wait for anybody else to reply or use advance search and find your answers.