Behcet's syndrome is a condition due to immune system disturbances. The mechanism is quite vague and a bit drd to explain however Behcet's syndrome is said to be in no association to any infection and is also not recognized as hereditary but it is has been observed among first degree relatives. So if the worry is passing the disorder to the child, it is not definite but there is odds of possibility but very rarely.
Another cause of worry I guess is on the quality of sperm due to the effects of medications he was on especially the colchicine. Colchicine is known to make alteration in cell division but its effects on pregnancy such drug is not clear as there is no adequate study done that I know of on that, so much more that there is no study has been conducted on how it affects the quality of sperm .
We cannot tell as of now if there is a problem with the baby but I would say that there is a rare possibility. Try not to worry so much for now and just hope and pray that your baby is okay. Worrying too much can have great impact on your baby.
Colchicine mostly can affect the quality of the sperm. There can be reduction of sperm production and the motility of the sperm may be decreased as well. It can possibly cause infertility.
As I mentioned earlier, Colchicine can affect cell division. There is a certain study which found colchicine treatment did not affect spermatogenesis. Check this link: http://humrep.oxfordjournals.org/cgi/reprint/13/2/360.pdf
So far there is no study on the effects on the fetus while the father is taking colchicine during the fathering period.