Going to see an elder law attorney before FIL moves in. What questions do we ask? What arrangements do we need to protect ourselves?

Will you be acting as his POA? For financial. Then you need a good solid POA written and signed by him with his agreement, what his own private spending account will consist of, what monthly statements and rundowns you will supply him of his assets in and his expenditures out. You need a written and signed care plan. you will need meticulous records and accounts so that any future needs for medicaid will deliniate how his expenditures NOW are not gifting, but rental and board, you need to know YOUR OWN tax repercussions. You need to know how to keep records for him. You need an understanding that this works, his living with you ONLY SO LONG AS it works for ALL THREE of you. At the point it doesn't work for all three, then it is off and he moves to assisted living.
Your father in law will not be getting better or remaining static and you need to understand that things now will decline, not move up. All your contracts signed sealed and delivered work ONLY SO LONG as your FIL chooses to have you serve as his POA. Or until he can no longer, in the opinion of several doctors, act in his own competence.
You need to understand that SIL and BIL have no say, no rights to know anything, and have only the right to ask wellness checks from APS. IF/when this happens bring out all your documents and welcome them into your home. Then that will be over with quickly.
You need on your own to discuss boundaries. What private time do you and husband require together, unless there is an emergency. And etc. Basically anything you can think of to add to the list add it.

Your FIL cannot contribute to the upgrades if Medicaid maybe needed within the next five years. Medicaid looks at this as a gift because you will eventually profit from the upgrades when and if u sell the house. There will be a penalty for the gifting. If you feel Dad will be with u over the 5 yrs then no problem.

I would insist that your husband should make sure his PoA is activated with the least amount of effort ("durable" so that it is not necessary to get an actual diagnosis of incapacity). Although once all FIL's paperwork is in place I would make sure he goes to have a cognitive exam. Make sure FIL creates an Advance Care Directive (Living Will) with his doctor, not an attorney. Make sure hubs has a copy as does his doctor's clinic. Have FIL make your husband his Medical Representative so that HIPAA rules won't prevent FIL's docs from discussing his health issues without FIL being present. This is different than MPoA. Have everything you agree on financially with him in writing. Discuss Medicaid qualification with the lawyer and protect FIL's ability to qualify at all costs. Make sure you understand it, it differs from state to state.

In addition to the the information and advise already given - if father is in need of additional care - are you care for him without being paid. If there is any possibility of either you or hubby charging FIL then you should also have the attorney provide the personal services contract. This has been a bone of contention between my hubby and me - he thinks I should - but I'm not so much.

Basically make sure everything is spelled out, keep meticulous records and don't worry about the rest of the family - as long as you you have good records and do your best by FIL you should be fine.

Pretty much, you tell the atty exactly what you have written here. Will there be a problem with his money paying toward renovation of your house? What kind of documents do we need for the romm/board? If we need to hire aides later on, give us a contract to use - and information on how to report earnings/tax info.

At some point in time he may have to go to nursing home - unless he has enough money to cover 24 hr care. You need to be sure all your t's are crossed to avoid any financial problems or assistance with Medicaid if his money runs out.

A lot of answers seem to address how to be sure your FIL qualifies for Medicaid which I don't think is your question at all. It sounds like you are more concerned with ensuring that his other adult children do not accuse you of financial mismanagement or abuse.

What help are they offering toward their father's living situation and care taking needs if they develop? You have not indicated that they are involved.

Keep careful records of how your father:s money is used, whether for "rent" or needed modifications for his own safety. If you have careful documentation of care and expenses, any frivolous accusations his other children may make will prove to be unfounded.

Imho, what you have shared with the forum is what you should share with the elder law attorney.