I let Liam die every time but once, when I was on Melissa's route and the kid was named Liam. (the only time I ever did a non-Megan run)
I find the guy annoying and irritating most of the time in the game, and unless it's a forced scene, I always ignore him for calls, texts, hanging out, etc. and I always have my MC call him out on the Angela/Hedwig SNAFU.
I understand you have to have a wide cast of characters and what not, but he's 40 and still acting like he's in his DIK days. I guess I take things a little too seriously, but hey, that's me.
"Don't Go Away Mad, Just Go Away." - which is how I feel about Liam in this game.