Why should he do so?
It is a normal behaviour, so there woud be no penalty.
If you want to improve your other website link profile, try these:
get links from domains hosted on IP addresses other it’s own (host them on separate servers if possible)
get links from a textual context
do not link just to homepage
choose a good link text
try link text relevant ...
Peter, first it's important to remember what John has already said. It's your content that ranks, not your domain name per se.
That said, it looks as though your newly acquired domain has quite a few backlinks (moz.com) and ranks for several key words. Assuming your own site has similar content and you want it to rank for the same key words, I would ...
If you set "International Targeting" to "United States", it could boost your visibility within the United States, but it will completely remove your site from search results everywhere else in the world.
You usually only want to use that option if you are ONLY targeting a specific country. For example if you can only ship your products within that country....