The property purchased by Mr. Prashant in 1996 will not automatically become HUF property merely because the purchase money came from his share of ancestral property. Once ancestral property is partitioned and a coparcener receives his defined share, that share becomes his separate/self-acquired property, unless he clearly throws it into the common hotchpotch of a new HUF. There is nothing in your narration to suggest that Mr. Prashant treated this property as HUF property after purchase. On the contrary, the facts point the other way: he purchased it in his individual name, executed a Will dealing with it as his own property, and specifically recorded that his sons were separated and earning independently. This is a strong indicator of self-acquired property.
Because the property was held and dealt with as an individual asset, the Encumbrance Certificate correctly reflecting the name of “Mr. Prashant” (and not “Prashant HUF”) supports the conclusion that it was never treated as HUF property. In Karnataka, when property is clearly recorded as HUF property, revenue records and ECs usually reflect the karta/HUF description. The absence of such a description strengthens the individual-property argument.
As regards the sons, Mr. Rakesh and Mr. Prakash do not have any surviving legal claim over the property. First, the property was self-acquired. Second, Mr. Prashant executed a Will giving only a limited life interest to his wife. Third, after his death, the sons themselves gave no-objection for khata transfer in favour of their mother, which amounts to conduct acknowledging that they were not asserting ownership. Fourth, Mrs. Prashant, as absolute owner after the life interest (or at least as a person with testamentary power), executed a registered Will in favour of her daughters, which was acted upon in 2005. That Will has never been challenged. Finally, the daughters sold the property in 2013, and the title has since moved to a third party. At this distance of time, any claim by the sons would be hopelessly weak, both on merits and on limitation.
The practical problem you are facing—non-availability or unknown whereabouts of the sons—is a banking risk issue, not a pure title defect. Banks often insist on Consent-cum-Confirmation Deeds from sons as a matter of internal policy whenever ancestral funds are mentioned in the chain, even if the law does not strictly require it.
Where the sons cannot be traced, the usual alternatives are:
a detailed legal opinion/title certificate clearly explaining why the property is self-acquired and why no consent is legally required;
a declaration and indemnity from the present seller (Mrs. Uma) indemnifying you and the bank against any future claim from the sons;
reliance on the sons’ earlier NOCs given at the time of khata transfer to Mrs. Prashant, if copies are available;
in some cases, a public notice in newspapers calling for objections, followed by completion of the transaction if no objection is received.
There is no legal mechanism to compel consent from persons who are untraceable or possibly deceased, nor is such consent mandatory in law in a case like this. If the bank remains rigid, you may either negotiate acceptance of indemnity and legal opinion, or consider another lender with a more pragmatic approach.
In summary: the property is not HUF property; the sons have no subsisting legal claim; the EC supports individual ownership; and the demand for consent is a risk-management requirement of the bank, not a statutory necessity. A strong title opinion coupled with indemnity is the correct way forward where consent deeds are impossible to obtain.