Is it normal much older man wants to use viagra?

I'm in my early twenties and he's in his early 50s, thanks to family and responsibilities, we don't get much time to spend together, but occasionally we'll have an afternoon off. At the start, he was only into my pleasure, which was both flattering and disheartening because I wanted to satisfy him as much as he did to me. He also eventually told me that he was having emotional issues getting hard, which I was completely fine with and said it doesn't matter.

Recently we had some alone time and he was kind of hard, and we started having sex for the first time but he stopped it because he wasn't fully hard, and I was totally okay with it and said it doesn't matter.

We text a lot, and I think he's getting the idea that I really want sex, and I think he does too, but I guess I'm just a bit hesitant using something like Viagra because it seems a bit of a cheat way to get an erection, and although I don't think it's dangerous, I don't like the fact it's unnatural and has potential side effects.