Brake bleeding problems

Hi there I live in Bali Indonesia and am trying to help a friend sort his brakes out. 1986 Suzuki forsa. In the UK it would have been scrapped 10 years ago but in Indonesia they don't have scrap cars, they run them "long after there dead"

After his mechanic friend put new seals in the rear brake and master cylinder, brakes still no good. Spongy.
I've checked seals in master cylinder, seamed OK, and put new seals on other back brake as leaking. Whilst his friend put new seals in master cylinder, the back brakes I am 99% positive were not bled.

Bear in mind this is a third world country, and cost is critical, a dollar here is like $100's in the US, so I have to be carefull what I recommend to him.

We bled the whole system front to back, used about 2 liters of fluid, (some of my old fluid which has been stood about 2 months so should be OK), A friend told me it should be OK after 24 hours standing to let the air out? But that was 45 years ago when I used to spend each weekend at his house with problems with his mini cooper S, a long time ago.

Tried again today, thinking air locks in the master cylinder, so loosened each brake pipe to the master cylinder to make sure fluid came out of each one of the two holes, the front one had air in and I thought I cracked it, but despite bleeding about another 5 times all round using over a liter of fluid, its still spongy. The brakes do NOT get harder when you pump them! Which I find strange. We've bled them both with the engine running and without. It’s just had a new servo fitted by some bozos, which I turned round as the pipe from the reservoir was a bad fit as blocked by the suction pipe from the inlet manifold.

SO? What next. When you press the pedal the fluid does not raise in the fluid cylinder thereby ruling out backpressure from the master cylinder? Unless the movement is so small, or taken up by the 2 rubber pipes from the master cylinder reservoir to the master cylinder, or the front two hoses to the brakes expanding! But they seem OK, I suppose they could be expanding, but is difficult so check.

There is something I am not familiar with, a junction box where the 2 pipes from the master cylinder connect to the 4 pipes serving the brakes. It seems to have some form of cap on top maybe plastic, the junction block I assume maybe some form of valve or diaphragm for safety if the front or back brakes fail, I don't know, could there be a bleed nipple under the cap? I don't think so but ADVICE ON THIS MAY BE HELPFUL before I remove the cap with a sledge hammer.

I told him to try it for a week pelan pelan (slowly slowly) till he gets some more money (maybe $30) to buy a new master cylinder and a new liter of heavy duty brake fluid. AM I MISSING SOMTHING OR IS THERE SOMTHING I AM DOING WRONG? Any help would be great.

My friend is a headmaster at a local village primary Hindu school, and is a very nice man.

Kind regards in anticipation.

PS you ask for a donation, Even with petrol at 50 cents a litre out here ( I'm on a pension, and the car is for a friend on about $300 a month (Primary school Head as well), perhaps one of the few honest people in Indonesia. Sorry no donation, lost too much with stirling since Lebanans collaps, now on about 66% of original pension, with prices quadrupled in the last 5 years in Indonesia.