Daycare vs nanny? (Grandma)

Hi all! My sweet 8 month old son has T21, diagnosed at birth. He’s the light of our lives! He is currently in daycare surrounded by “typical” kids, which we feel is likely great long term for his development. It’s obviously expensive, and my mom is retiring soon and has offered to essentially be his nanny, which would be a great way to save money. I wonder though if it would be detrimental to take him out of daycare where he has so much exposure to peers. I know she could always do play dates library classes etc- wondering wha you thoughts were. I myself was never in daycare- just preschool, but not sure how experiences vary for T21 kids. He is also an only child so far. Curious to know your thoughts!