Do you know the name of the younger brother? (I suppose you do since you found him in two censuses.)It is hard to search for people with such common names when we have few clues. ;-)
I see two men with the same last name emigrating from their parish on the same date. One is Carl, a name often Americanized to Charles. He was born in 1867 and not 1866, however, and they left in 1887, not 1886. This is a longshot since the cd I'm using is only 75% complete and nothing matches exactly. You will probably have to find more clues.
The vast majority of the 1890 U.S. Census burned in a fire. Do you perhaps mean the 1900 U.S. Census? If so, that census provides a month and year of birth.
Emibas:
Emibas was made from registrations in the Swedish parish to go to a foreign country.
Bondson = son of a farmer. Län = county.
Post 372657
Mattisson, Carl Johan
Bondson (unmarried man)
b. 7/18/1867 in Asarum, Blekinge län (Blekinge)
Emigrated 12/23/1887
from Långasjönäs 86, Asarum, Blekinge län (Blekinge)
to Amerika
Source: Household Examination Roll, p. 639
Emibas migration file ID: Asarum K 1887 040
Post 372659
Mattisson, August
Bondson (unmarried man)
b. 12/20/1869 in Asarum, Blekinge län (Blekinge)
Emigrated 12/23/1887
from Långasjönäs 86, Asarum, Blekinge län (Blekinge)
to Amerika
Source: Household Examination Roll, p. 639
Emibas migration file ID: Asarum K 1887 039
I have no idea if these two are yours. I checked Emihamn, which was made from registrations with the Swedish port police before leaving Sweden. This appears to be the same people except now Carl is called Carolina,the son of a farmer is now called the daughter of a farmer, and the original two year difference in age has become a four year difference in age. It is obvious that there is an error somewhere and the parish records need to be checked.(I suppose it is also possible that these are two separate pairs of people and that the ones found on Emibas didn't use a Swedish port when they left. Swedes often used ports in Norway, Denmark, and Germany, for example.)
First name: CAROLINA
Last name: MATTISSON
Age: 22 Gender: K
Parish: ASARUM County: K
Title/Note: BONDD
Port: MALMÖ
Date: 1888 02 23
Destination: NEW YORK
Fellows: JA
Source: 1888:70:3108
First name: AUGUST
Last name: MATTISSON
Age: 18 Gender: M
Parish: ASARUM County: K
Title/Note: BONDS
Port: MALMÖ
Date: 1888 02 23
Destination: NEW YORK
Fellows: JA
Source: 1888:70:3108
Try the Swenson Swedish Immigration Research Center to find more clues. They have a website but their extensive record collection is not online.
http://www.augustana.edu/swenson/ Judy