hey no offense i mean this in the best way but if someone you love is talking about stuff you don’t understand and is very passionate about it (like idk nuclear energy or astronomy), you can a) listen anyway even if you can’t add anything because they’re probably just happy that someone can hear them b) ask them questions about it so you understand if you’re interested because they will surely be willing to answer and happy that you care
you may not care but it means the world to someone that you’re willing to just, listen, when anyone else would just not care about being nice to them about their interests.