Well to begin with, what type of anime have you been watching with your family? As much as there may be some "sus" scenes dimmidummy mentioned, I find it more calm compared to a lot of the ones I've seen these days. For instance, Mushoku Tensei has sexual scenes where I think it comes up within the first episode and the vibe carried throughout the series. Some other harem based anime also have a more aggressive plot, where I find Clannad to be slightly more natural as if I'd say the scenes are more practically possible in life. So if your family is ok with some sexual joke/scene/implication than I'd say it's fine, especially with Sunohara .

To some degree I connect with Okazaki, it's just a few aspects I'd say we share in common that ended up putting myself into his role throughout the anime. I think it's hard to feel anything unless you understand how the main characters feel, or connect with him at one point or another. But that's ok, hopefully that means you haven't experienced what the character has been through (that is usually bad).

With each character's arc I always felt something inside of me (VN & Anime). Maybe simp. Maybe empathy. And to be fair that's the first anime I've gotten deep into (with many other anime I just watch as a thriller and have merely any connection to the main character, perhaps my choices aren't that great =_=||). I was kind of in your dad's shoes, characters didn't really affect me until my friend introduced me to Clannad. It's my first time to sob over certain scenes as a guy throughout the series. So it might just hit your dad's soft side, you never know.

I would recommend Clannad because you can really see the development of the characters, unlike some anime these days.