[Ahnya]

din really try to understand the full story. my impression is like this, not sure if it's correct:

A passed away intestate, so there're problems with his inheritance.

B was given away, not sure with all rights and ties severed legally and entirely. had already inherritated from rich adoptive parents, now wonders if aso can claim from biological family members. not willing to fight in court for the small sum.

C is the one with 3 children doing medicines, instigated other siblings not to give shares to B. he's the bad guy.

a very interesting plot for mediacorpse tv dramas which are currently rather boring

I think it's B whose 3 children are in medicine. 
I think someone mentioned that B is 62 y o, in which case the children should already be practising doctors,  not students