sale of home from divorce

I recently had a client who qualified for the exclusion 25 years after the divorce decree, that allowed his ex to live alone in the jointly-owned property until she decided to sell it.  

IRS Pub 523

 Separated or divorced taxpayers. If you were separated or divorced prior to the sale of the home, you can treat the home as your residence if:
You are a sole or joint owner, and
Your spouse or former spouse is allowed to live in the home under a divorce or separation agreement and uses the home as his or her main home.
If your home was transferred to you by a spouse or ex-spouse (whether in connection with a divorce or not), you can count any time when your spouse owned the home as time when you owned it. However, you must meet the residence requirement on your own. If you owned your home prior to your marriage and after your divorce or separation, and your spouse or former spouse isn’t allowed to live in the home under a divorce or separation agreement, you can count any time that you owned the home, solely or jointly with your spouse, as time when you owned it. However, you must meet the residence requirement on your own.