Pretty hard to beat a Stockman pattern (3 bladed), round bolsters for everyday carry, of 3 inches length, slightly more or less. Grip/handle width slim for dress wear, wider for field use.
The better steel always a good investment, if money not a problem. Quality stainless of good repute, if everyday carry also.
Name and date engraving also a good idea. If he has it years from now, and doesn't get stolen or lost, it will warm his heart to know he has something from Mom in his possesion daily, and will want to remember the year Mom gave it to him.
Beware the bells and whistles and the salemanship. You want functional quality that is made to last. Find someone who knows steel and about who made the knife to shop with you, if you are not savy. Lot of junk out there.
Also, advise him to never loan it
out of sight. You would be surprised how easy it is for out of sight to disappear. Hence the engraved name,
.
