ITR of pensioner where TDS deducted doesn't seem to be reported

My father is a central govt (ministry of defense) retired person who is immobile now, and a pensioner. The Form-26AS from IT dept site shows pension income and consequent TDS deduction for only 9 months, that too with reporting of pension-payment and TDS twice for the month of Apr'2020. The statement of bank A/C where he receives payment, clearly indicates that he received as much pension as he would after TDS deduction, for all 12 months of the AY21-22. I am at loss as to whom to approach and what to do, to correctly do his ITR filing, since IT dept might flag it as insufficient TDS, while it appears that TDS sum has been deducted but not reported. Any guidance in this regard would be highly appreciated.