Voters should choose whom to vote based on policy positions, experience and ability, not based on age, sex or other criteria irrelevant to performance. This is as true for older voters as it is for younger voters. Support for Sanders, or any candidate is a personal preference, not one to be made as an age bracket.
A Bernie Sanders presidency may indeed improve material conditions for most older voters, but this doesn't necessarily mean they should vote for him. Perhaps these older voters want a more economically libertarian environment so the young have greater opportunity. Maybe they will prefer a candidate less friendly to identity politics. In any case, older voters are diverse in their values, and their votes should reflect that diversity.
While Bernie Sanders seems to have a great record and campaigns for taking care of the American public, I believe supporting Bernie Sanders would be a wasted vote. Older voters should not support Bernie Sanders on his ideals alone, they must consider the likelihood of Bernie Sanders winning the national elections and being able to follow through with his ideas of how to improve our country. A vote for Bernie splits the democratic ticket and may mean a vote for Trump in the end. Definitely, not a good ending for the elderly.
No, older voters should not be supporting Sanders. While Bernie Sanders may be the older of the two Democratic candidates, it is my opinion, that older voters should not support him just because of age. If they identify with him over Hillary Clinton on relevant policy issues, they should vote for him, but I do not believe that any voter should support someone based on a characteristic such as age, gender, or race.