I have looked into it. That said, I don't think either of my dogs matured with the temprament to be therapy dogs. My rescue Sparky gets excited and barks too much and Lucky gets agitated at other dogs. (long story ... I now blame all his issues on my druggie ex-dog walker ...)
We have talked about doing Therapy with my sister's English Toy (aka King Charles) Gemma. She has the PERFECT temprament for therapy.
A couple things to keep in mind:
1) most organizations require a dog to be at least a year to do therapy
2) if you decide to feed Raw to Fletcher then Delta is not an option for you (I feed my guys a dehydrated raw). Delta does not allow raw for what they claim to be sanitary reasons.
Good luck. I'd just focus on training now and when he's a year old if he's doing great and capable of passing his Caninie Good Citizen class, then he'll likely be a great prospect for Therapy.
(a.k.a. Lucky's & Sparky's mom!)