Thanks for your replies - sorry, yes, you're right - I meant that he can check in online for the LGW - malaga leg.

My thinking is that if the vancouver - gatwick flight leaves on time then there's a decent chance it'll arrive on time, and at least if it's leaving late I'll know he's going to miss it and can book him on to a later flight before he even lands in Gatwick.

I guess there's never any way of knowing how long your baggage is going to take to appear.

If he does end up tight for his connection, what's the best strategy for making it? Is it worth asking for help, and who should he ask?