What to get

What to get a month old for valentine? We have 2 other kids(9,2 years old) and my 9 year old wants to get his baby brother something for Valentine’s Day. My baby is premature and still in the nicu for right now, hoping he’s out by the end of this week, just working on feedings. So my oldest hasn’t been able to meet or see him so we wants to get him something special that he can keep forever to show him how much he loves him and couldn’t wait to meet him. But I’m not sure what to get