Hi cambojnr, if I re call you have a 60 litre and 20 litre tank?
As we have already mentioned in the other thread, these are too small for shubunkin's and goldfish in general.
As Shubunkin and other single tailed goldfish can grow up to 12 inches, with most fancy types of goldfish generally reaching 10 inches.
The rule of thumb for fancy goldfish, is 20 gallons/80 litres for the first fish and then 10 gallons/40 litres for each additional fish thereafter.
For single tailed goldfish I would double the above rule, as they are much more active and I would also add, that single tailed fish are better off in ponds. They can be kept in suitable aquaria as juveniles and may be kept in large aquaria (tanks of at least 6 foot in length) as adults, but ponds are the ideal situation.
If your neighbor doesn't have room for all 4 shubunkins, then you could always look into other people in the area that may have space for them, perhaps ask in local fish stores, or find a local aquaria club, or even a fish rescue service can sometimes take in fish.
There are lots of options
Also it's generally a bad idea to mix single tailed fish and fancy goldfish.
This is because fancies tend to be slower moving and will be out competed for food by the single tailed fish and possibly even stressed by their more agile and quick movements.