Ways to enhance sperm count??

Kaitlyn • Surprise! Baby number three on the way! Twin sisters who are about to both become big sisters!
Hi! Any suggestions that y'all have heard from a dr or in the community on ways for my fiancé to "enhance" his sperm count/mobility? I've heard folic acid, which I've been taking myself for a month but he refuses to take them too. He's cut back pretty drastically on cigs, so I've heard that helps too. 
​Any other ideas?? Without trying to "push" him on any of this or "make" him change too much. 
​Thanks guys :)