“One son with DMD”

Can you please help me? Had a son who passed away from Duchenne MD. I am not a carrier and my second son did not have DMD. Then 12 months after our son died I was diagnose with late onset MD. Totally different from DMD, but it's never been diagnosed as to what type it is. Just that it affects the whole body. I started having problems around the age of 35 when I couldn't get out of a chair or up off the floor, etc. But could this MD I have be passed on to my second son? He's always been very healthy, but because he can't get his wife pregnant, this so-called doctor that my son sees wants my son to have a biopsy. I can't believe this, I can't stop crying. This can't be possible. Please help.