What do you mean by "SS classification" ?  Even with zero pension and IRA income, 85% of his Social Security would be taxable.  Are you trying to do retirement planning for him, not just tax planning?  Sure, he might have been able to wait to start collecting Social Security.  And he might have been hit by a truck tomorrow.  Or he might live in Texas and froze to death after contracting Covid.  When my clients ask me when they should start collecting Social Security, I first ask them for their date of death.