1. it will be better if all the cheques are drawn by your dad only.
2. because he will be named the 'releasee' in the release deeds
3. if the payment is made by his family members but in the deed he is made the releasee, then such a transaction will come under the purview of a benami transaction which is prohibited under the Benami Transaction Act
4. what can be done is you and your mom can transfer money to your dad's account
5. all of you will show the above amount as 'gift' in your books of account
6. your dad can then use this money to pay his siblings under the release deeds