Possible ASD or speech delay.

[Babydevelopment1]

I have a 2.5 month old lb. his older sister has a diagnosis of ASD and is non verbal.
My lb doesn’t point for things but he is starting to point at pictures in book to show me. He does wave bye bye and for hello. He is following one step instructions, plays with toys appropriately and constantly babbles, he is making proper sounds for some words but doesn’t use them consistently. He has excellent eye contact and is interactive with his siblings, he is making slow progress in all areas. He looks for praise, if he wants something he will bring me an object or toys to play with him. He has been with a speech therapist and because he is making progress they are not concerned with sending him for a diagnosis. He has been out down to an expressive language delay. He is not where he should be at but if I compare him to my autistic daughter he is the complete opposite.
Can anyone please advise if they have been in this situation before and did their child get a diagnosis?