I would say go out and test drive a few 

Toyota and Lexus and Honda seem to be reliable 

My first choice would be an Abrams tank, but because that's not likely to happen ...

Toyota Highlander, Toyota Rav4, Honda CR-V, Honda Pilot would be within the first group of candidates.

Then possibly look into Subaru Forester, Kia Soul. The last 2 are small or sub-compact SUV's functionally limited to 4 persons plus some luggage.

It's also a little difficult to make an appropriate recommendation with knowing more details, such as intended usage area (urban, suburban, rural), number of persons and/or amount of cargo to be transported, expected usage (in miles) per day/week, special considerations (such as wheelchair ramps, folding steps, etc), financial resources available for purchase, time frame in which purchase is to be made, and others.

In some circumstances, I may even recommend a vehicle such as a Chevy Suburban, or perhaps even a pickup truck, versus an SUV. It all depends on what is really needed/desired by the user(s).

However, one meaningful consideration would certainly be whether an AWD or 4WD vehicle would be preferred for safer operations in winter conditions. If a 2wd vehicle is considered, I would certainly suggest that the vehicle be equipped with a limited-slip differential. I would also recommend purchasing a vehicle capable of using snow chains (you'd be surprised how many vehicles can't fit or use them).

Also, I wouldn't necessarily be seeking a safe vehicle for seniors, but a safe vehicle for people, or anybody.

Hope this helps ...