1. Since the house is registered in the name of your brothers they are the absolute owners thereof in spite of the fact that your father pooled his retirement money to build it and that your elder brother made no contribution whatsoever..
2. Your father cannot remove your elder brother from the house as the latter is a joint owner of the property.
3. The only legal recourse available to your younger brother and father is to file a case for declaration of ownership in view of the fact that your elder brother did not spend a penny in building the house. The proof of the amount having been spent by your younger brother will help them in the court.
4. Your father and younger brother can evict your elder brother from the house only after a court of law holds that your elder brother is not the joint owner of the house. Till that time your elder brother has all the rights of an owner.