[cheebacheeba]

No point grabbing too many moving/mobility based toys right now.
You want useful?
A small plush toy, nothing flashy.
MANY washcloths.
A few onesies.
Buy some stuff for the mother. Snacks. Easily accessible energy.

You want something big?

Buy them a nebuliser, they'll probably need it at some point. Helps a LOT with congestion if/when they get sick.

Tit pump.

If they don't have one, a bottle sterilizer for when the kid gets onto formula or bottled breastmilk.

All the best to you and yours with the kid.