You could always take a break from trying for a few weeks and then try again or let him watch his sister eat and pique his interest. Another method of feeding that I found interesting is called "baby-led weaning".
Don't confuse this with the idea of letting a child nurse and wean from the breast or bottle on their own.
Basically--instead of pureeing and trying to spoon feed, you give the child large pieces they can palm and suck, gum to introduce them to new tastes and textures.
Here are some other links--maybe your child will just want to jump right in with table food! Many children insist on table food after a few months on puree. My daughter and daycare child both switched to table food around 9-10 months old.