Does he like or despise or is in between about jewelry? No, I'm not a spammer. It's just that if you think a pendant of some sort with engraving could possibly work for him, or even something like his father had, a trip to a serious jewelry store could help you decide, one way or another.
When we got married, low on money as usual, we used my grandmother's thick gold band for me, and none for him. We did have it engraved for us inside the ring. Some time later, we went to a well known jewelry store in Beverly Hills, and popped for a platinum rather modern band for me. We both liked it and soon he went to a neighborhood silversmith's garage business (this is in Venice, CA, lots of artisans) who replicated one for himself, in silver, us still being cheap. He was a good silversmith, and I still have a cluster of quite dear items from over the years.
NOT that you need to go cheap - I mean that really good jewelers can at least give you ideas.
A pendant or engraved art work may be smarter than a ring.