our boy is about to be diagnosed with asd my wife is pregnant

Hope said:

While it is preferable not to have the condition, IntenseWorld is right in saying that, with the right support, any difficulties can be massively minimised and a child can have a happy life, and grow into a productive adult.

I'm not sure that I'd even go as far as to say "preferable not to have the condition".  It would very probably be easier not to have an ASC.  But, to paraphrase from Malcom Reynolds in Firefly, there is a difference between the losing side and the wrong side.  Would the world really be a better place without any autistic people?  How much are our lives made difficult by autism per se, and how much by a lack of appropriate support and facilities and/or the way that we are treated?  Should the latter be attributed to autism?  (Rhetorical questions)

For the OP, they have the big advantage of a diagnosis in childhood, and with what they've learned from the first child they'd probably notice and get an early diagnosis if the second child is autistic.  That increases the likelihood that they'll get the support that they need.  Even "severe" autism doesn't mean they can't be happy e.g. see the family with twins with classic autism in this video.  They have a lot of challenges, but they're happy: www.youtube.com/watch.  

To use a very "everday" example of how autistic people can enjoy life and contribute, I saw a video once about an autistic guy in America who got a job as a cleaner because he absolutely loved vacuum cleaners.  He even knew exactly what kind of vacuum cleaner all of his parents' friends had!  His dad said that this job was the equivalent for him of being paid to sit around watching TV and drinking beer.  Getting paid to do what you love like that must be everybody's dream!

Hope said:

While it is preferable not to have the condition, IntenseWorld is right in saying that, with the right support, any difficulties can be massively minimised and a child can have a happy life, and grow into a productive adult.

I'm not sure that I'd even go as far as to say "preferable not to have the condition".  It would very probably be easier not to have an ASC.  But, to paraphrase from Malcom Reynolds in Firefly, there is a difference between the losing side and the wrong side.  Would the world really be a better place without any autistic people?  How much are our lives made difficult by autism per se, and how much by a lack of appropriate support and facilities and/or the way that we are treated?  Should the latter be attributed to autism?  (Rhetorical questions)

For the OP, they have the big advantage of a diagnosis in childhood, and with what they've learned from the first child they'd probably notice and get an early diagnosis if the second child is autistic.  That increases the likelihood that they'll get the support that they need.  Even "severe" autism doesn't mean they can't be happy e.g. see the family with twins with classic autism in this video.  They have a lot of challenges, but they're happy: www.youtube.com/watch.  

To use a very "everday" example of how autistic people can enjoy life and contribute, I saw a video once about an autistic guy in America who got a job as a cleaner because he absolutely loved vacuum cleaners.  He even knew exactly what kind of vacuum cleaner all of his parents' friends had!  His dad said that this job was the equivalent for him of being paid to sit around watching TV and drinking beer.  Getting paid to do what you love like that must be everybody's dream!