One possible theme could be redemption. Maybe the old man has made mistakes in his past life and the counterworld gives him a chance to make things right.
One main theme could be adaptation. The old man has to adapt to the new counterworld he finds himself in. Another theme might be self - discovery as he learns about his new abilities and place in this strange world.
I'm not very familiar with a specific 'old man in counterworld light novel'. You could try searching on some popular light novel platforms like J-Novel Club or Novel Updates. Maybe you'll find it there.
There's 'The Ancient's Tales' where the MC is a wise old man. The story focuses on his wisdom and how it influences the events and characters around him. It's a great read if you're into this kind of character.
Sure. 'Sword Art Online' has some parallels. It's set in a virtual world which can be considered a kind of counterworld in a sense. The main character has to face various challenges and grow in that world, just like the old man in the 'an old man in counterworld light novel'. Also, 'Grimgar of Fantasy and Ash' might be relevant. It shows how characters deal with a new and often harsh world, which is something that the old man in your mentioned novel also experiences.
Well, perhaps the hero in this light novel is overly cautious in making decisions. He might hesitate a lot before taking any action, always weighing the pros and cons carefully. This could lead to him missing out on some opportunities at times, but it also might prevent him from making hasty and dangerous mistakes.
I don't have access to the reviews of 'i became the hero's mom light novel' directly. But often, in light novel reviews, people will comment on things like the uniqueness of the concept. In this case, the idea of becoming the hero's mom is quite novel. They may also talk about how the story progresses, if there are any unexpected twists, and how well the author has built the world within the story.
I'm not entirely sure as there could be many light novels with that title. It might be about a world where there are no traditional heroes, perhaps exploring a more complex view of society or characters who don't fit the hero mold.