Suggested modifications:
- True stainless steel chain not just anti rust coating. (Waxed if you can teach him how). KMC Z1X INOX is an example and do not fit your bike.
- Change every single bolt to stainless steel A4 quality. Tighten using correct Nm and grease. Where steel meets aluminum use the proper grease!
- Change to ceramic sealed bearings in good quality especially for the BB.
- Long-lasting easy to maintenance pedals
- Stainless steel and teflon coated wires and hoses.
- In recent years I have used tires branded "Duro". They seems to be lasting more than twice compared to medium brands and I paid $10 for a set. Tubes with antiflat liquid. Make themtires/tubes one class thicker than normal. (Like change european 700x25c to 700x28c or even 700x32c)
If I was shopping for those parts, an estimated price would be around $100.
Estimated worktime for you (not for newbies): 3 hours.
Estimated extended life time: 2-3 times as long as without modifications.
An easy way to extend life is cleaning and lubrication. Teach him how. If you know how, you can do it within 30 minutes once per month. Upload a video to vimeo and make thousands of cyclists happy.