I just sent my first letter through InmateAid. How will I know when he receives it, and how long does it take?
There is no delivery confirmation or read notification for prison mail. Once the letter is sent and has not been returned, the assumption is that it reached him. The only way you will know for certain he received it is when he mentions it in a call or writes back.
On the timeline, InmateAid estimates 2 to 3 business days for the letter to travel through the US Postal Service and arrive at the facility. That is only the first leg. Once the letter gets there, the mailroom staff opens it, reads it, and inspects it before it gets cleared for distribution. How long that takes varies from one facility to the next, and there is no way to predict it from the outside. Some mailrooms turn mail around quickly, others sit on it for days.
Mail call at most facilities runs Monday through Friday, so weekends add to the wait. Factoring in transit time and mailroom processing, a total of 5 to 10 days from when you send to when he holds it in his hands is a reasonable expectation, though it can be faster or slower depending on the facility.
Be patient and keep writing. The letters get there.