You don’t say what you’re using it for, so you could really just roll a dice or toss a coin. But I would go for the touchbar model. Sure the RAM is lower but for most cases 8GB is fine. In return you get a faster processor, faster wifi, touchbar, and more ports.
And I think the SSD might be quicker but I’m not sure.
Its up to you ultimately and we cannot decide for you.
Think what you really need:
-TouchBar or Function keys?
-Stuck with 256GB or Upgradable SSD?
-8GB RAM or 16GB RAM?
Should be pretty easy to decide if you answer yourself the above questions.
For 4 years with his use he will be more than fine.I’d go with the 16GB. nTB can Turbo Boost to 3.1 GHz and stay there all day long, no issues.
16GB will make it future proof.