Has anyone ever tried to make a parent-in-law your dependent? What were some obstacles during the process? How long did the process take?

Case by case, if you can prove you can match the secondary dependent income $1 for $1 and you have proof like bank statements or allotment AND you provide more the 50% of there support for hospitals, rent and utilities. Approval guaranteed! Also, if the secondary has 0$ income Is a Bonus automatically approved if they live with you. BUT, If they received ssi, retirement, and disability and they can’t afford their bills and your income match there income and more, you will be approved.
Hope this helps!

I only know a few people who have succeeded in this. The biggest obstacle is proving that you consistently provide over 50% of their living expenses. If they don't already live with you, it's probably not going to make the cut.

Sir, when I was enlisted I did go ask questions about it on post for my mother in law. They stated it would have to be a matter of serious illness or a lack of ability to take care of themselves. Paperwork (proof) would be needed. It's a lengthy process I was told.