Oh for the love of all that is holy... for a bunch of people that do not want to tell him how to live, that is all I hear... lol
Look, your towing capacity is 6500. The boat easily weighs close enough to that. 2 things you need to consider, besides getting the brakes fixed is this:
1 - If you can tow 6500.. and if it weighs 6500... then any bump, hiccup, extra ice chest etc.... and the torque of that will exceed the 6500. I have to go pick up my truck today that had service on it and I asked them to check the transmission because I wanted to make sure it was doing what it is supposed to do. They can tell every bump on the load the truck has within seconds. If you tow and that thing exceeds the range and the transmission is hurt, I can guarantee they will be able to tell and will deny any claim so....keep that in mind. I suspect you will end up replacing that transmission in the toyota within a year.... a hell of a lot more expensive than brakes or a new vehicle.
2 - You should have a minimum of 10% of your max towing left after all said and done....on a good day... with brakes. No way you have that.. so... consider that.
Lastly... do what you feel comfortable with... at the end of the day, if you are alone.. no-one else around.. then no-one else pays the cost of repairs heh.. I have seen trucks tow crap they would/should never have been able to tow.. does not mean they should, just is what it is.
Make friends with someone that has a bigger truck and ... "you have the boat, he has the truck"... great symbiotic relationship and always have a fishing partner
Or, trade the toyota in and get a Ford.. lol
one boat I bought...I had a corolla... wife asked, "how do you plan to tow the boat?"....."Funny you should ask that..." took me a week before I could look her in the eye again
GL!
Russ