Firstly, while adrenaline and determination are a factor in strength and endurance, should that only apply when his brother is actually at risk? You also need to specify it more. Enhanced strength and endurance could be anything from a mere weightlifter to freaking Whitebeard (the latter would of course not be allowed).
As for techniques, the fruit states things he is in touch with. This would seem to prohibit area effect attacks such as the "anti-gravity" move. Further, it leaves question if it is "moon gravity" (weaker gravity) or actually reversed gravity.
Does Moon-Blinding cause damage, or just blind? Further, does it only blind those it hits, or all those who see it, or something in between?
Moonlight just needs more explanation in everything. Why does this happen? Does this have an actual effect? If not, why is it a technique? If yes, what is the magnitude of this effect?
Self-gravity is fine.
As for internal gravity, I don't think that fruit can affect parts of an object, especially parts you're not actually touching. Further, until something exerted force on the person, the organs wouldn't be going anywhere.
Also, as a sidenote. Homicidal grudge against the whole marine organization for some stolen ransom money? Sounds kind of excessive. Is your character intended to hold such disproportionate grudges?