For the recently widowed, it probably is a good idea to "eat out" on a regular basis, since some have a tendency to hibernate at home and lose "social contact" that really is helpful.

"Socializing" your recently lone(some?) one can be a rather delicate matter, but even if it's just encouraging their going to a nearby greasy spoon on a regular basis it may let them at least see other people, even if the personal interaction is minimal.

An ideal situation would be to find a compatible "victim" to trade off cooking for both. With someone occasionally available with whom insults (about the food) can be exchanged, the learning process can be greatly accelerated. There's no need for the victim(s) to be "intimate," and often there are good reasons why they should not.

Some "senior clubs" I've heard about have had "cooking parties" for which each person is given a simple recipe to prepare for a (preferably small) pot-luck session. In small doses, these might be helpful.

While it's essential for all, especially for elderly cooks and most especially for inexperienced elderly ones - MAKE SURE THE SMOKE ALARMS WORK. For most stove-top flameups, a box of baking soda actually works about as well as a fire extinguisher, but it would probably be a good idea to have at least a small BC¹ extinguisher near at hand just in case.

¹ In the US at least, fire extinguishers are rated A, B, C depending on whether they're suitable for "paper and wood," "fuels and oils," or "electrical" situations. The BC is good for oils and electricals and is what you'll want in the kitchen. The A class is better for flaming walls and curtains; but if used on a hot stove the "A class" material leaves an impenetrable fused-on residue that's extremely difficult to clean up. Common retail outlets often have only the ABC rated ones, but a boat or RV seller likely will have the BC rated ones better suited to kitchen use. Put the ABC in the bedroom/bath and garage areas. Your elder should be able to clean up as easily as possible, so that the "what fire?" response can be used for anything really minor. (experience applied here...)

John