Who should keep the titles?

Before namatay ang lolo ko, he asked my mom to keep the titles for him, and so my mom did. 10 silang magkakapatid.pero mama ko lang ang tumutulong financially sa lolo ko at that time para mabayaran ang taxes ng lupa. After lolo died, mom took charge of filing up the papers and payments needed with the help of his 2 brothers financing the amount of tax that are ought to be paid. And now my aunt and uncle wanted to keep the title. They want to sell the lot ,they also want the share of my lola, kasi sila daw ang nagbabantay sa kanya ngayon. My lola's 95 y/o now, and cannot make her signatures right. Mama ko nagbabantay kay lola for 5yrs. Nung april lang nila kinuha sa mama ko si lola, july pa lang ngayon, 3 months pa lang ganyan na ang iniisip nila. Pera pera pera.. They even told my mom that they're not gonna give her a share. Can they have the title? Or can they even sell the lot that easy? What should my mom do? What are her rights?

If the title is still under the name of your lolo, ALL the surviving legal heirs has the right over the property. They cannot easily sell the property nor transfer the title under their names because they need first to execute "Extrajudicial Settlement of Estate", wherein all the legal heirs may divide the estate among themselves. If the heirs do not agree on how to divide the estate, the case may be up for judicial determination through the filing of an ordinary petition for partition by any or all of the heirs with the proper court. (Rule 74 of the Rules of Court)

"What are her rights? "
The most important question is what rights has the gready aunt = Nothing or very small as long as your lola is alive.

Your grandmother is alive, so she own more than half anyway.
" Can they have the title? Or can they even sell the lot that easy?"
Not legaly (if they don't FOOL your grandmother to agree to sell, then there are SOME risk they can get it through.)

You say "titleS". Is it possible to SPLIT them, so them, who want to sell, can get their share WITHOUT llola's home is sold?
Did your lolo and lola get 2 kids?
Can your mother prove lolo gave her the control?
If all these are "Yes" then I interprete it as this:
Beside the right lola have to use the property, she OWN at least 1/2 + 1/8 = 5/8
1/8 to your mother and 1/8 to your aunt.
Then it's 1/8 left, which is some unclear, but the "control" Yes, I interprete as lolo wanted your mother handle it but belong to lola. If so 3/4 belong to lola.

If one heir can prove she has paid biger part of the tax, then she can ask for compensation, but I don't know what a judge/captain would decide about that.

"What should my mom do?"
/Ignore the annoying aunt
/OR suggest the aunt can get her 1/8 part, if (roughly) such split is possible, but then she has to make sure the aunt SIGN she had got that before the split which will happen when lola die.
/If either of these functions ok enough, she can ask the Baranggay Captain for assistance to try to solve it. Then he/she will ask the involved for their oppinons.