It's quite usable at 350Kbps. I have a Sling set up in the UK and the max upstream is 384Kbps. It's never videophile quality but it's good enough. I actually find it better for movies and such. Sports move so quickly that the compression codecs can't keep up at low bandwidth.

Have your mother check with the cable co. Likely there're 'premium' options that will give you 512 or even 768Kbps upstream. The small bump makes a HUGE difference. I find the sweet spot to be 768Kbps. Beyond that you see improvements but they diminish in magnitude. If Verizon FIOS is available, that'll give you full 2Mbps bandwidth and it'll be like you're THERE.