If down the road I have to put my husband in a nursing home will my 401/retirement be at risk?

My wife of 36 years has advance multiple sclerosis, and I tried to understand what my options were - I hired a professional care manager. She assessed the situation and proposed a couple different insurance options. She also explained who a recommended Elder Care attorney was, who I also hired. Through them, I've made arrangements to enroll my wife, now in a local nursing home, in a Medicaid program based on her income. My assets are protected via a spousal impoverishment provision. I'm a very frugal person and saved a majority of of salary. My spouse was the opposite and had a very minimal savings. Thankfully this program exists and I don't have to work till I'm no longer able and/or exhaust all my resources to provide for her care. Seek out a good care manager (National Association of Professional Geriatric Care Managers) to get some really good advice.

Now is the time to sit down with your financial planner and discuss things like putting assets in a Trust and other ways to protect what you have. Whether or not the 401K is at risk depends on what your TOTAL assets are and how you structure your withdrawals.
Also sit down with your attorney and set in place POA's and Advanced Directives. Review your Will as well. It's time for all that.