My sister in Nebraska has been receiving Social Security disability payments for several decades. Her disability amount is more than her retirement amount would have been since she was disabled relatively young. I believe her SSDI is currently somewhere around $1,600/mo. or so. She was also married to a man for more than 10 years who earned much more than she did for a much longer period of time. They have been divorced for more than a decade. She has never remarried and has difficulty making ends meet as SSDI is her only income. She turned 62 in April 2016. Her ex-husband turned 64 in Dec. 2016. I do not know if he has yet filed for Social Security. I doubt it since I believe he is still working full time. I don't believe he has ever remarried either, so he might be eligible for ex-spousal benefits himself at FRA. Supposedly her SSDI will remain the same amount and automatically turn into a SS retirement benefit when she reaches FRA. Is there any way to check to see if she would be eligible for a higher amount either now or when she reaches FRA by filing for ex-spousal benefits? I suspect half of his would need to be more than all of hers to help her any, what is sometimes called an excess spousal benefit. Over a year ago I considered whether she would be able to file a restricted application for just spousal benefits at FRA by dropping her SSD, then let her own grow until 70, but believe the 2015 rule changes closed that door. Plus I wasn't sure her own SS retirement benefit with delayed retirement credits would be any more than SSD or ex-spousal benefits. Any advice you can give that could increase her benefit now or in the future would be helpful. So far all I know for sure is she would be entitled to divorced spousal benefits if he ever died which isn't likely any time soon. Thank you.
If your sister's disability rate is $1600 monthly, she would almost certainly not be eligible for divorced spousal benefits as long as her ex-husband is living. This is because she would only be eligible for a maximum of the higher of her own disability rate, or 50% of her ex-husband's full retirement age rate (PIA). And, even if her ex-husband had the maximum possible earnings subject to Social Security taxes, his full retirement age rate would be well below $3200. In theory at least, his PIA could get that high in the future, but only if he continued to work and have very high earnings until around age 80.
So, it sounds like your sister is receiving all that she can from Social Security for the foreseeable future. Regardless, though, she could certainly check with Social Security to see if she might qualify for divorced spousal benefits, or even file a claim in order to receive a formal determination. She could also suspend her own benefits when they convert to retirement at her full retirement age, but she could not receive divorced spousal benefits while her own benefits are suspended. She could then resume her benefits at age 70, at which time they would 32% higher, but I'm assuming that she couldn't afford to be without any benefits for 4 years.
As you indicated, though, if her ex-husband dies before she does, your sister could then become eligible for up to his full benefit rate, inclusive of any delayed retirement credits that he would earn if he waits past full retirement age to start drawing his benefits. Except for that possibility, however, it doesn't sound like your sister has any other options with regard to Social Security.