Where factory warranty issue is concerned, it's best to retain warranty rights by adhering to 'uncommon sense' factory recommendation of Oil Change Interval and 6 months/1 year duration.

For those out of warranty, one may stretch OCI's in km or goes beyond 1 year duration stipulation.
Other than uneconomically costly and impractical UOA's , I'd adopted free and easy Blotter spot tests to assess used oil conditions.........
realising along the way  that factory recommendations are excessively conservative and short.
If the car is out of warranty , short answer is stretch it to say, 1 year or longer.
Long answer.

Sorry , I can't follow what you mean by 'critical stuff' ?
Forget about what Toyota says about 6 months duration change, be it for fullsyn, semisyn or mineral .....
as we don't cold temperatures or winter seasons.
Toyota's recommendation on 10000 km oil change interval is for fully synthetic.

Now , your brother's car travels 4800 km per year.
I would suggest you use any SN/SM/SL mineral oil for 5000 km or 1 year, and that's being conservative.
If it's my car, I would pick a mineral A3B4 oil for 8000 km or 2 years.
You don't really need fully synthetics or semi synthetic in this low use car.

Engine oil details?
Good idea from you, 

In your case , follow mileage will do , not time as we always heard as Malaysia never had winter or for that matter spring/autumn where cold temperature promotes corrosion.

You may consider using a cheaper semi synthetic for 2 years of 10,000 km usage, IMO.

Note: Our minimum ambient temperature is 24*C, vs gwailous winter temperature up to -40*C or lower , go figure.

Note2: I had seen a few UOA's of  4-7 year old used engine oils on Bitog that demonstrates tip top condition.

Hi Jamespaul,
During 1970/80's , local OEM SC's had been recommending oil filter life of 10,000 km (i.e 2 oil changes @ 5000 km) till todate with use of API SE/SF oils and obsolete manufacturing technology such as 'metal finishing' on contacting components like crankshafts, camshafts, piston rings and piston liners.

As I understand it some (not sure if it's all) Europe VW and MB recommends 30,000 km oil change with Long Life oils like VW 50400 50700, MB 229.5, MB 229.51 etc but not sure about filter change intervals unless some readers can confirm it.

There maybe a 'progressive' OEM SC in KL recommending 15,000 km filter change coinciding with oil change,I don't know and I would like to know if there is any local OEM SC recommending 2X10,000 km or 2X15,000 km filter change.

I'd personally extended filter change to  17,138 km as per my blotter spot tests here with 280k ODO and I strongly believe my blotter is 'clean' enough for extending further filter change interval.

Instead of theorising and speculating on this one may spend chunks of money on UOA and Particle Counts or a  cheapo blotter spot test for better 'feel' .

Edit:With my limited knowledge on how oil filter works in our cars, I don't buy the concept of extending oil change interval by replacing oil filter  mid way of OCI.
I wouldn't be surprised if 30,000 km filter change interval is recommended in Europe, IDK.

You have to take into account that Europe's fuel and engines are designed for Euro 6 already with less sulphur in the fuel. Their oils also call for low ash formulation.

For our Malaysian roads, most of the time our driving falls under "severe" category due to heat and stop & go traffic.

Hi Guys,

One thing i do not understand that Shell Helix Ultra 5W-40 vs Shell Helix HX8 5W-40. Both are full sync. But why price wise different by so much? Around RM100 per bottle. Any diff? Are they both giving the same performance?