Both my teenagers have mac books... they love them.
Games, iTunes, ArtRage, Photoshop, MSN Messenger, e-mails, ToonBoom basic, iMovie,Text Edit and Word for writing homework, Googling stuff... thats the sort of things they use them for.

I have only ever had Macs in the past and use an iMac now.
Poser8 runs a treat and ZBrush 3. Vue Complete plays nice now and all the various Adobe apps I use are fine .
At my kids school they use Windows based PCs and so have on occasion brought school work home in weird formats.
But since we found a great online conversion site even that isn't a problem anymore.

The biggest thing for me is I rarely have to spend time providing 'tech support' for them and for the brief 6 months my son had a Dell/Windows laptop it seemed thats all I did.
The entire family ended up hating that machine for all the headaches it caused.
But I have friends who use both Windows and Macs for work, generally they have a Mac at home.

Of course hard wear can screw up and users can themselves cause all kinds of messes on a computer regardless of platform ... but everyone knows that.

So I'd say Yes, recommend a Mac toyour cousin .
And 'Lalala' earplugs so that the snide things some WindowsPC users feel they need to say about Mac users goes unnoticed ; )
If he/she needs to adapt to a Windows PC later  then they can do that.

" Try and be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try and live together in peace and harmony with people of all creeds and nations."
-Monty Python