Forgive me if I am misunderstanding or being dense-but is T applying for his "own" disability benefits? Because he is also (perhaps) eligible to receive his dad's as survivor benefits since he is disabled. (see below)
"When you die, your family may be eligible for benefits based on your work.
Family members who can collect benefits include a widow or widower who is:
60 or older; or
50 or older and disabled; or
Any age if he or she is caring for your child who is younger than 16 or disabled and entitled to Social Security benefits on your record.
Your children can receive benefits, too, if they are unmarried and:
Younger than 18 years old; or
Between 18 and 19 years old, but in an elementary or secondary school as full-time students; or
Age 18 or older and severely disabled (the disability must have started before age 22)."
He may be eligible to apply for both his own disability benefit plus benefits as a survivor under his fathers record. I'm not sure if he can be paid 2 benefits-but if not- the SSA defaults to the higher $ amount. If he gets benefits under h's records - you may be eligible to receive add'l payment as his caregiver.
Again-sorry if I am stating something you all ready knew. I'd rather err on the safe side and be redundant!