Hello there. first of all, congrats to your brother  .

anyway, the duration of his study can be seen in 2 ways.

1. Degree duration.
2. Duration to obtain license.

1. Degree duration :
take the BACHELOR OF AIRCRAFT ENGINEERING TECHNOLOGY (HONS) MECHANICAL for example link

-it will take him 4 years to get the degree.

2. Duration to obtain license :
tihs one on the other hand it's a whole lot different story. there are 2 different views here depend on what is going to happen to MIAT in the next 6-8 months.

a) View no. 1 : if miat is just what it is right now which is, NOT AN Approved Training Organisation, it will take your brother 4 years(degree+taking exam as an outsider via DCA)+5 years(to gain aircraft experience) before he gets his LWTR (License Without Type Rating)

b) View no. 2 : if miat can get the ATO status in the next 6-8 months or in 4 years your brother is going to be there, it will take him 4 years(degree+taking exam as an ATO candidate)+2 years(working experience in the aviation maintenance field before he gets his LWTR.

I suggest you ask him to read a lot about the DCA Part 66, EASA Part 66, and etc. all of the details from duration, subjects, modules, and etc.

if i were him, i will use his diploma right now and join any airlines/chartered flight/helicopters/flying school companies as their low level technician and while working, he study on his own to complete all 12 modules (for B2 license) and after complete all required modules for the license he's going to apply for and after 5 years within the company, he'll then submit for his LWTR.

i might be wrong in any info here, do correct me. thanks