Reddit mentions of 2XU Men's T:2 Team Wetsuit

I'm in the US, so I unfortunately don't have any recommendations for shops or anything like that. My wetsuit experience involved going to a local sports store that does rentals and trying on a couple. I'm smaller than your mother - 5'4", size 14 at the time - but they had things that worked for me (and I wasn't the largest available size).

2XU's Men's T:2 worked really well for me. I tried on a couple of others - one from BlueSeventy, and I can't remember the other brand - and they just didn't fit me right. Not too tight or too big, necessarily, just space where there shouldn't be space but perfect in other areas and too long for me overall. Here's my mildly-embarrassing first-ever-wetsuit photo. I was really surprised that a men's wetsuit ended up being appropriate for me and my decidedly non-men's-shaped body, but hell, bodies are weird. :)

Having a salesperson who could walk me through the very intimidating wetsuit process was a huge benefit for me. If trying one on isn't an option, though, and your mother is built at all like me, I'd recommend 2XU's line.