With that sort of build to me it looks like the absolute best he can do is something like this:
Psion1/Sorc4/Dragon Disciple 10
This is a 15th level character, so he should be very powerful. Now lets look over what he has.
Assuming a starting point buy of 30 (I dont have any idea what you use) the character might be something like this:
Str 14 +8 (class) +3 (level) = 25
Dex 10 = 10
Con 14 +2 (class) = 16
Int 14 +2 (class) = 16
Wis 12 = 12
Cha 14 +2 (class) = 16
HD: 5d4+10d12 +45 (avg 124)
BAB: +9
Full attack: +16/+11
Skill points: 4*(2+int) psion list, 4*(2+int) sorc list, 10*(2+int) dragon disciple list
Saves: F: +11 =+3 (stat) +8 (base), R: +4 =+4 (base), W: +14 =+1 (stat) +13 (base)
Spells: As a 4th level sorc + 7 extra 2nd level spells per day (known:6/3/1, PerDay:6/7/11, DC 10+3+level)
Powers: As a 1st level psion of whatever discipline (3 1st level powers known, 3pp, DC 10+3+level)
Special: 4th level familiar, bonus feat from first level of psion, +4 natural armor, breath weapon 1/day, low light vision, 60' darkvision, immunity to sleep and paralysis, immunity to energy type of breath weapon, claw/claw/bite routine, blindsense, wings
This is the absolute best that he is. Before that last level of dragon disciple he is missing out on quite a bit of this and every level of something after this will have to be a beginning level from some other class or a very marginal boost to one of the two other classes that he has.
He is still missing his 3rd attack (and will be for 2 more BAB) and his attack bonus is 'very' low for a primary fighter.
His casting ability is almost nil, essentially it will only be for utility work or slight bonuses that can be dispelled very easily.
He does however have some interesting options here and there and if he starts off as a human then all of the later abilities are all gain.
Likely it could be a very enjoyable character, but it is 'very' far from being a powerhouse. Looks to be a bit under par overall to me. And this is when he is at his absolute maximum potential (barring some really cool prc after this.. such as warmind..mmm..)