Unfortunately there is nothing that can be done. tie Court system is broken. There are too many cases for to few Judges. when you spouse comes to this same realization you will have a settlement. Until that time your case may linger in court
If you can prove to the courts that either you, your attorney, or a private investigator can not locate your spouse, then you can proceed with a divorce by publication. This process is tricky, so consult with a matrimonial attorney asap
I suggest that you file and serve an amended summons or verified complaint with the grounds of irretrievable breakdown of your marriage. This is much easier to prove, and takes less time. If your husband decides to fight the case, the Judge will make it difficult for him, filing under this ground has the same effect as cruelty.
It should go to you and your siblings, howeve, if he creates a will he can leave his share to whomever he chooses. If your uncle does not have a will, you will need to go to surrogates court to establish your rights after he passes.
I assume you are talking about social security benefits. As long as you were married for more than 10 years you would be entitled to collect under your ex husband's benefits if that amount would be higher than the amount you would be able to obtain on your own. If you are talking about his pension or retirement benefits, it depends on the language in your settlement agreement. If your divorce judgement or settlement agreement was silent on this issue, you would not be entitled to any of his...