I the US they have something called a Spousal Impoverty Act http://www.medicaid.gov/Medicaid-CHIP-Program-Information/By-Topics/Eligibility/Spousal-Impoverishment-Page.html http://www.nolo.com/legal-encyclopedia/medicaid-protections-spousal-income-during-long-term-care.html so that if one spouse is in need of Medicaid for care, the other spouse is allowed to keep the house, their own income/assets, and half of all shared assets as well as an income so that the non-ill spouse can continue to live in their home and not have to suffer becoming impoverished due to the other spouses for medical care.
Well, sort of. The "community" (living in a regular community, non-institutionalized) spouse can keep the house, if the couple owns one (equity $543K or less, so, plenty for most Americans), one vehicle, their own earned income, and half the (other) shared assets up to $117K. If they don't have their own income, they're guaranteed access to somewhere between $1.9K but not more than $2.9K/month in income (depending on the state, the min/max are federally established) from their spouse's income.
If the community spouse has retirement accounts and is drawing from them for living expenses, they may be protected (sheltered on top of the $117K shared assets), depending on the state. They also may not be. If they're not in "draw down" (the beneficiary hasn't started taking payments from them) then they are considered "available" like other assets(!). If they are in the name of the spouse who needs nursing home care, then regardless of their status (draw down or not) they are considered available to pay for that care, even if both spouses were planning on using them (or are using them) as a source of income in retirement.
If the community spouse has other income-generating assets, e.g., rental properties -- tough luck, they count as available to cover costs that would otherwise be covered by Medicaid, except for the $117K protected amount.
So -- yes. The "community" spouse is protected in that they can keep the house (if they own one), a car, $117K, whatever they earn, and an additional somewhere between ~$2-3K per month in income, provided that the income comes from somewhere sheltered, like their own 401K or a spouse's (traditional) pension, or Social Security.
If they don't
have their own retirement account (or for that matter, own their own home), or there's no pension or not much in the way of social security, well, there's no protection to bump their income
up to $1.9K. So for some, the protections are -- adequate if not fabulous. For others, not so much.