1-year-old baby life jacket?

It sounds like there's been a confusion, but your question is spot-on — 1 year is a critical water safety age.

Short answer: when choosing a life jacket for a 1-year-old, the most important features are type and weight class, not brand. Here's what to look for:

• Type 100-150 Newton (EN 13138-1 standard): For a 1-year-old, it should be a "life jacket," not a "swim aid." The vest must have enough lifting power to flip your baby face-up and keep her face out of water. Low Newton (like 50N) is just a pool helper, not safe in open water.
• Choose by weight class: Look at the weight range clearly marked on the vest (like 9-15 kg). A jacket that doesn't match your baby's weight is dangerous — she could slip out, or it won't lift her properly.
• Between-leg strap is required: The strap must go between the legs and attach to the belt. Belts-only designs let babies slip out.
• Neck/head support: A high collar that prevents the head from tipping backward is good.

Your mother-in-law probably means something like a ring float or arm bands — those are absolutely not safe for 1-year-olds in open water, they can flip instantly. If she's saying "any brand works," that's not right either — many products don't meet safety standards.

The safest way is to pick one meeting these criteria, show it to her, and check the label together.

One more note: a life jacket is never unsupervised protection. You must stay within arm's reach, keep eye contact, and watch constantly.