Refer the couple back to the current pastor in charge. If they insist seek the blessing of the current pastor in charge. Seek the current pastor's consent if not blessing. When a pastor has a close relationship to with particular folk, it is simply wrong to say anything, even in jest about inclusion in a senior's will. When you are asked to serve as an executor for an estate and you think that you will be able to direct funds to your congregation you are setting yourself up for conflict of interest.
Sexual sin is never far from the door and sexual temptation is probably knocking.
Guarding against the appearance of evil is very important. Do not initiate a hug, and if you do, ask first, and if you do, hug around the shoulders briefly and not too tightly. When counseling do so safely. Don't set yourself up by counseling alone, in a locked room, out of sight, etc. You won't regret it.