Personally I think reusing a sibling name is not acceptable. There are thousands of names to choose from and your second child deserves his own name. I was the younger sibling and I was never really a jealous kid, but I remember sometimes feeling like nothing was truly mine - clothes were always hand-me-downs and even experiences were things my older sister had done first. At least I had my own name though.
From my older sisters side, I know she sometimes felt I'd come along and taken everything that was hers - her mum's attention, her favourite toys, that pretty jacket that didn't fit her anymore - but at least I hadn't taken part of her identity - her name.
Hopefully your kids will be lovely together but sibling relationships can also be really fraught, and I can imagine this being used as ammunition in a sibling fight from both sides.
If you really love the name you could maybe use it for your younger sons middle name and that would be a nice connection, but I think its a really bad idea to use it as a first name.