I'd go with the .260 or 7MM-08, either would be great deer calibers!
I go against the grain on 30/30's for beginners though. Unless you will be with them at all times or he will be shooting ONLY at short to short/medium ranges. While the recoil of a 30/30 may be great for youngsters, the bullet drop is too much for someone that doesn't have good experience at range estimation. A good, flat shooting, low recoiling gun like the .243, .260 and 7MM-08 (and a few others too) would be a much better choice! Good luck!
Frank