I guess it depends on exactly what anti-catholic book it was.
Catholicism and Fundamentalism by Karl Keating is a great one. It’s a little on the longer side, though, so if your friend gave you a short booklet, it wouldn’t necessarily be an even exchange. It can be a bit dense of a read at times, too. If your friend gave you Lorraine Boettner’s “Roman Catholicism”, though, this would be the perfect book.
Scott & Kimberly Hahn’s
Rome Sweet Home is shorter and an easier read. It’s their conversion story, but it gives a lot of great apologetics in the process.
You could also try Thomas Howard’s conversion story
Evangelical is Not Enough. I’ve not read it myself, but I always have heard great things about it.
Whatever you get, make sure you read through it first before you give it to them so you know what they’re getting. If you don’t have time, you can at least skim it beforehand and then try reading it at the same time in case they have questions.