• If I file and suspend now, at age 62, would my wife (age 49) collect spousal child-in-care for my disabled adult son (disabled before age 22) at a rate equal to half of my early (age 62) retirement benefits?
• Would my disabled adult son also collect benefits at that rate?
• If my wife took spousal child-in-care now at that reduced rate, would she still be able to take her full spousal benefit at age 67 (i.e., at 50% of my full age-70 benefit, when I plan to retire)? Or would she be forever stuck at 50% of the age 62 benefit?
• If my son took the disabled adult child benefit at that reduced rate now, would he still be able to take his full benefit at 75% of my full age-70 benefit, when I pass away, or would he be stuck forever at the lower benefit?
• My son already receives SSI disability benefit payment of $7536 per year. Would that be subtracted from any SSA benefit he would receive as an a disabled adult child?
• The sum of my age-70 benefit and my wife’s benefit is likely to be very close to the family maximum. If there is no room to take the disabled adult child benefit, wouldn’t we want to preserve that benefit nevertheless? (I.e., would that benefit continue throughout the lifetime of the disabled adult child?)
• Whenever I pass away, would the right strategy for my wife be to switch to a Widow benefit because she would then get 100% of my benefit instead of 50%?
You can't file and suspend at age 62. You could file and suspend at full retirement age (FRA), but your wife and child couldn't get benefits on your record while your benefits are suspended.
When you do start drawing, even if you take reduced benefits prior to FRA, your wife and child could each be eligible for up to 50% of full retirement age rate, but would likely receive less than that due to the family maximum benefit (https://www.ssa.gov/OACT/COLA/familymax.html).
Your next 3 questions are based on the premise that your spouse and child would receive a reduced rate if you take benefits at age 62, which isn't true. Regardless of when you start your benefits, whether it's at a reduced rate at 62 or an increased rate at 70, your wife and child's benefits would be based on a percentage of your full retirement age rate (PIA). However, as a widow at full retirement age, your wife could receive up to your full rate, including delayed retirement credits (DRC) if you wait until age 70 to apply. But, if you take benefits at age 62, her potential widow's rate would be limited to no more than 82.5% of your PIA (https://www.ssa.gov/planners/survivors/ifyou5.html).
Your son's SSI benefits will be reduced essentially dollar for dollar by any disabled adult child's benefits that he receives on your record (https://www.ssa.gov/ssi/).
If you wait until age 70 to start drawing benefits, the benefit increase of up to 32% that you would receive as a result of delayed retirement credits would not count toward the family maximum. Your PIA would be subtracted from the family maximum amount, and the remainder would be split evenly between your wife and son.
In the event of your death, your wife would likely want to continue drawing child in care survivor benefits until her full retirement age, and then switch to unreduced widow's benefits at that time. However, if you start drawing before your full retirement age or if she is entitled to benefits based on her own work record, that could change what she'll want to do. Your son's disabled adult child's benefits can continue for as long as he lives.