He's MFJ and claims his income this year will be 44k.
So he can take his income 44k, his trad ira 46.5 = 90.5k
In order to stay in 12% you have the 25k standard deduction and up to 80k in income. 105k.
Since 90.5 is less than 105k you can do it, and the marginal rate for your conversion is 12%. And since you'll be a well paid lawyer that's worth it.
Roth is also helpful because you can avoid big RMDs later in life and you can stay in a lower tax bracket even when you have "lumpy" expenses. i.e. you are trying to stay under 65k for ACA reasons and you need your roof replaced, just take it from the Roth. Also nicer for heirs to inherit a roth than a Trad.
1) The roth conversion is a no brainer
2) Selling taxable for roth, less so, especially if you want to access money for retirement before 59.5. BUT - Are you going to be making 180k plus after school? If so, I'd lean towards selling the taxable for roth too since you'll have plenty of money to fill up a taxable bucket later anyway. You will probably pay zero percent gains in 2022 and maybe other years too. The gap gains rate is 0% until 80k
https://taxfoundation.org/2021-tax-brackets/