Would you use your brother in laws sperm?

So my husbands brother is gay and is happily married to his partner of 15 years (they’ve been married for 3 years) They used a surrogate to have their son. The surrogate was his husbands sister. She heard they were looking into it and wanted to do it for them and it was way cheaper than typical surrogacy because she was also the egg donor so they didn’t have to do <a href="https://glowing.com/glow-fertility-program">IVF</a>, just <a href="https://glowing.com/glow-fertility-program">IUI</a>. We recently found out my husband has extremely low sperm count and the chances of us conceiving naturally are slim to none. My husbands brother has now offered to be a sperm donor for us. I am so incredibly mixed on this. I get why he feels it’s appropriate since they used his husbands sister as a surrogate/egg donor and it worked out great but it seems too weird for me. What do you think? Would you consider it? I hate that I’m so conflicted about it because I love him so much and am so thankful to have such a selfless, loving, brother in law.