I believe he came to the states via Ellis Island in the early 1900's (1912-1915...). He married Kazimiera after arriving, and they lived in Wilmington, DE raising 12 children.
Thank you all for any information you can provide!
On the Ellis Island page records I've found two Dalecki Jan's trips - first 11th April 1905 from Antwerp, second 4th May 1939 from Hamburgh, May 31 1918.
They can't be the same person (although possible related) since both were 20y old at the time.
Your timeframe suits the older Dalecki more. Another valuable information could be the name of relative he is joining. It's very hard to decipher it, but my guess would be (uncle?) Gabriel Wojtulewicz/Wojtukiewicz? Check yourself - third name from bottom