SBC424
Systemic reactions to BCG are "rare", and more importantly, there is a wide range of severity to such systemic reactions.Once the more common "annoying" systemic reactions (such as my reactive arthritis reaction to BCG) are taken into account, the frequency of severe systemic reactions is seen to be tiny.
Below is a link to a current article, "Clinical Spectrum of Complications Induced by Intravesical Immunotherapy of Bacillus Calmette-Guérin for Bladder Cancer". This article could be frightening since it discusses so many possible complications, or it could be reassuring since it notes that so many of the complications are understood and addressable. It is always necessary to be selective in reading medical articles - so many feature fear rather than facts; the link is to a database by the National Institutes of Health.
www.ncbi.nlm.nih.gov/pmc/articles/PMC6431507/
If family members have risk factors that are of concern, you need to discuss the issue with your personal doctor.
You note that a first BCG treatment was given immediately after TURBT, and that 6 more will follow. Typically BCG is not given untll some weeks following a TURBT, and the full induction course is of 6 total treatments, not 7.
By all means, do have a full discussion of ALL your concerns with the urologist and family doctors about your any family health issues that might be impacted by BCG. Only your doctors will be able to consider the full extent of your specific situation.
Hopefully, the article link will help in describing the risk of complications.
Best
Jack