Need some advice

I don’t see a problem and I’d open his new tablet! People get on my nerves with all that screen time mess!

I dont see a problem either my son has an iep for speech it doesn't make him any less smart or cause any change in him.

I don't see a problem either. Unless he's fully dependent on it and has been showing behavioral changes towards you, then it becomes a problem. Simple phone calls or small visits doesnt show true issues.

If he wants to know what is going on in school he should ask the teacher. Does the school send out anything about what happens in school or have an app? My daughter’s pre k had an app and her kindergarten teacher sends an email every week about what they did in school. I think kids deserve a little break after school so I don’t see problem with screen time.

It's hard to see it as a problem when it makes life for parents so much easier and if you don't see the benefits to compare it to. Personally, I think he's requesting this quite respectfully and his feelings should be taken into serious consideration. At the end of the day, you both want what's best for him

Are you coparenting?
Because if dad isn’t even equally pulling weight with caring for your son, I would pivot the conversation to that and not a choice of technology; I don’t know the dynamics of course, but it isn’t fair for all the pressure to occupy him without electronics to be on you

Your child is in school, OT, and speech. I think it’s perfectly acceptable for him to have a break to spend some time enjoying his tablet. I would open it and allow him to watch it! Dad sounds a bit demanding.

As a speech and language therapist im gonna play devil's advocate. I think you both have a solid argument here.
Too much screen time can be addictive and isolating and certainly isnt doing anything to enhance your son's development...on the contrary, nursery will be hard for him as there are a lot of social and linguistic demands placed on him. Having time where these demands are limited is important and the tablet will be fulfilling that for him. Just set a limit on it.
Also dad should be mindful not to put too much pressure on him to report what he did that day as this can be hard for a lot of children, let alone someone who finds communication challenging. Agree that speaking with a teacher might be more helpful