As salaam o alaikum Mufti Sab
We have a question for you regarding family planning and is it permitted in our case?

Should we go ahead and ask the surgeon to tighten the tubes while delivering the fourth pregnancy? 

I have 3 kids, Ages(11,10,7).  Alhumdolillah my wife is pregnant with twins. All her deliveries were c-section surgeries. This will be her fourth c section.

Recently, i was diagnosed with a rare type of blood cancer. I am undergoing treatment for it. May Allah give me shifa , health and long life to take care my family. Aameen. Allah is the provider but kids need their father in this country.

I am scared that Allah swt will punish us on the day of judgement for tightening the tubes to avoid further pregnancies.

We need your guidance in this regard.

We live in USA.  Yes it is hard to raise 5 kids since i am the only bread earner. My wife stays home to take care of kids.

Any thoughts in this regard will be appreciated.
JazakAllah