In the properties left behind by our father at his intestate demise shall devolve equally on all his legal heirs. Now you say that two brothers were given money earlier by your father during his life time. That was his decision then as per his choice. That cannot be involved legally in the present partition issue, in the intestate properties, all the legal heirs are legally entitled to an equal share. If one of the heirs is magnanimous enough to give away his share to his fellow sibling, it his choice, he can very well relinquish his rights in it by executing a registered release deed in anyone's favor of in favor of all others.
To your second question: While asking a question what was the necessity to seek clarification for the provision in Indian law?, which law are you governed by? It is needless to say being an Indian you are governed by Indian laws only and not by a neighboring country law.
The property seems to have been transferred on his name by forging your father's signature?, do you have proof for it, if you have substantial evidence to prove forgery, you can file a suit to declare the said transaction as null and void but it should be done within three years from the date of such knowledge. You may consult your lawyer and proceed as per his advise.