It is quite possible that your male could spit out the brood prematurely if he is still young.
If he is still not eating around day 28 i start looking around in the tank for eyes with a yolksack.
They usually release the young either around dawn or dusk.
if you got a longspine urchin even better coz that is where they are hiding in in their natural habitat. You could build one out of zipties but when i tried the frie would never go there. They hang in the sandbed, near the bubbletip nems and in the middle of a tube nem....of course.
I fished mine out each morning and put them in a little hatchery in the main tank, later i worked out you can strip the eggs of the male on day 24 and put them in a egg tumbler with a great survival rate.
I start feedeing them 3 times a day with baby brine shrimp, in week 3 i would reduce that to 2 feedings a day.
I have 2 baby brine shrimp hatcheries going at that time alternating to have a constant supply of baby brine.
Eventually after 4 or so weeks i start introducing mini pellets and frozen food and ween them of the baby brine shrimp. To get them to eat the pellets and frozen i have oister eggs mixed in too, that is like chocolate for fish.
After 3 month my LFS takes them for store credit.
After the male released all the fry he only got about 10 to 14 days before the female wants to go again, depending on what quality food you give the parents.
Hope that helps a bit.
Here are some pics