The problem works out to a set of three equations:
b + c + d = 22
a + c + e = 22
a + b + c + d + e = 30

Solving for c = 14, leaving d = 8 – b and e = 8 – a. In other words, c must be 14, but the other two numbers just have to add up to 8. The requirement that they be unique rules out 4 + 4, so you’re left to choose from the following combations for b + d and a + e:
0 + 8
1 + 7
2 + 6
3 + 5

6 is 3 of course. Because six has three letters.

One = three letters
Three = five letters
Five = four letters
Four = four letters

Cosmic is a number that has the same number of letters as the value. Four is the only number I’m aware of that has this property.

The man in the picture is the onlooker’s son. Since he doesn’t have any brothers or sisters, the statement my father’s son can only be himself. A shortened version would be this man’s father is me, making him the father of the man in the picture.