Could someone explain kilo and pounds. When my mother weighs in they may say you gained 2k what is that in relationship to pounds?

A "kilo" is a kilogram, which weighs 2.2 pounds.

If your mother gained 2 kilos, she gained 4.4 pounds.

Most of the medical world now uses kilograms instead of pounds.

Some other useful information about liquids:

One liter of water weighs 1.0 kilogram (or 2.2 pounds).

One quart of water weighs 0.946 kilogram (or 2.08 pounds).

If your mother gained two kilos, she "put on a couple of quarts".

One gallon of water weighs 3.78 kilograms (or 8.33 pounds)