Some libraries have sewing machines. Your task sounds simple enough to DIY using GP's method on a shirt large enough to fit two.

http://www.mv-voice.com/news/2014/09/02/a-stitch-in-time-at-...

https://www.google.com/amp/s/sacbee.relaymedia.com/amp/news/...

http://sandiego.communityguides.com/content_mobile.php?pid=4...