There is no mention of who, why, or what made the changes. it goes all the way to deleting his marriage to my daughter. any suggestions.
In Tree select Recents and see if either/both are listed there. If your daughter and son-in-law still appear in your tree view but your son-in-law's tree no longer has parents and grandparents - you should be able to view Latest Changes on your son-in-law's profile and view what/who changed those profiles. Since I assume your son-in-law is Living - sharing the PID here in Community won't help. You might try setting an appointment with FamilySearch for tree help. https://www.familysearch.org/en/fieldops/familysearch-support-contact-us
They should be able to help you restore the tree view/profiles.
Assuming both your daughter and son-in-law are alive, then almost certainly what is going on is that you are working in or viewing in more than one account. All information on living people is private and can only be seen by the owner of the account who entered the information.
If you were signed into Family Tree and entered the information, you will see your daughter and son-in-law with one pair of ID numbers. If your wife signs into Family Tree and you look over her shoulder, your daughter and son-in-law will have different ID numbers and none of the information you entered under your account will be there.
This is just how Family Tree works in order to satisfy all the various laws around the world regarding protecting the privacy of living individuals.
If your son-in-law is still living, then only you should be able to see the profile you created for him, and you should not be able to see anyone else's profile for him.
I suspect what happened is that someone (not you) entered your son-in-law as deceased, you linked up to that erroneously-public profile, and then it got corrected to living and thus disappeared from your view, along with all of its relationships.