Okay so my fiance says he wants to be a dad and is excited to be on the journey but he skips meals, he doesn't drink…

Okay so my fiance says he wants to be a dad and is excited to be on the journey but he skips meals, he doesn't drink enough water I don't even think he drinks water at all and he doesn't eat enough fruits and veggies because he's picky. I have yet to get him checked to see how his sperm count is or his health and I'm just wanting to not take him to be seen but try making changes in my kitchen so his sperm is top healthy so that being said any tips? I'm really trying to talk to him about it but he makes it into a joke when to me it's serious especially with me having PCOS.